Abstract: This analysis was a correlational study using archival data that sought to determine if the state-wide election results for President, Governor, and/or U.S. Senate flipping from one party to another could serve as a reliable antecedent to, 1) state legislative chambers subsequently flipping to that same party, and/or 2) the state becoming a trifecta for that party. Further, it looked at whether there were consistent patterns in the order in which voting for candidates at different levels of office flipped. This study amassed a dataset of, 1) the state house, state senate, and Governor control for all 50 states since 2000, 2) each state’s U.S. Senate choices since 2000, and 3) each state’s presidential choice since 2000¹. Descriptive statistics were used to explore the dataset to look for patterns.

• Presidential votes: 
  • Between 2011-2020, when a state flipped its presidential party vote, this reliably foreshadowed a flip of at least one state legislative chamber (88.24%) and the achievement of trifecta status for that party (~87%). 
  • Between 2001-2010, when a state flipped its presidential party vote, this reliably foreshadowed a flip of at least one state legislative chamber, but to a lesser degree than between 2011-2020 (55.17%), and the achievement of trifecta status for that party (76.67%).
  • During the combined period between 2001-2020, when a state flipped its presidential party vote, this reliably foreshadowed a flip of at least one state legislative chamber (77.78%) and the achievement of trifecta status for that party (80.95%)
• US Senate votes: 
  • Between 2011-2020, when a state flipped the party of at least one US Senate seat, this foreshadowed a flip of at least one state legislative chamber (76.47%) and the later formation of trifecta status for that party (86.96%). 
  • Between 2001-2010, when a state flipped the party of at least one US Senate seat, this foreshadowed a flip of at least one state legislative chamber, but to a much lower degree than in 2011-2020 (48.28%), and the later formation of trifecta status for that party (73.68%). 
  • During the combined period between 2001-2020, when a state flipped its U.S. Senate party vote, this reliably foreshadowed a flip of at least one state legislative chamber (63.89%) and the achievement of trifecta status for that party (80.95%).
  • For trifectas that form after flipping a state legislative chamber (as opposed to flipping the governership), there also appears to be some support for a flip sequence of flipping the presidential choice, flipping at least one US Senate seat, and then flipping at least one state legislature chamber (66.67% overall and 83.33% for blue trifectas from 2011-2020). 
• Gubernatorial votes: Between 2011-2020, when a state flipped its gubernatorial party vote, this foreshadowed a flip of at least one chamber to that party (64.71%), but it is not a very reliable indicator of achievement of trifecta status (52.17%). In fact, it was approximately equally likely that states became trifectas after flipping a state legislative chamber or the governor’s seat during the 2011-2020 period. There does not appear to be support for a flip sequence of president, then governor, then state legislature. 
• Partisan lean: Several trends were more reliable antecedent indicators for Democratic chamber flips than Republican flips. In particular, 
  • Pres->Chamber Flip: Presidential votes in states tend to flip parties before at least one chamber of the state legislature does. Between 2000-2020, the pattern occurred 77.78% of the time (100% of the time for Democratic state legislative flips and 65.2% for Republican state legislative flips)
  • Pres->Chamber Flip among trifectas: 100% of blue trifectas formed after the state voted for the Democratic presidential candidate. 72.73% of red trifectas were preceded by the state voting for the Republican presidential candidate.
  • Pres ->Both Senate Seats->Chamber flip among trifectas: 66.67% of blue trifectas formed after the state flipped its entire US Senate delegation blue. 18.18% of red trifectas were preceded by the state electing two Republican Senators. 
• It is important to note that this data was naturally limited and nonexperimental. Further, it looked at a small period of time and had a small sample size, especially for analyses of interest like states that formed trifectas from 2011-2020. Another concern is that, in many cases, the presidential vote and sometimes gubernatorial vote flips decades before the state legislature.

Background and Research Question

This report examines trends at the statewide (governor, US Senate) and presidential levels that may act as antecedents to changes in state legislative control and/or trifecta status.  In particular, this report asks the following questions: 

1. Does a state flipping its choice of partisan in a presidential election tend to precede the state flipping partisan control of one or both of its state legislative chambers?
2. Does a state flipping its choice of partisan in a gubernatorial election tend to precede the state flipping control of one or both of its state legislative chambers? 
3. Does a state flipping its choice of partisan in a presidential election tend to precede the formation of a partisan trifecta for that party?
4. Does a state flipping its choice of partisan in a gubernatorial election tend to precede the formation of a partisan trifecta for that party?
5. Does a state flipping its choice for one and/or both US Senators tend to precede state legislative flips and/or the formation of a partisan trifecta for that party?
6. Do gerrymandered states tend to follow a different sequence?

This study was prompted by organizer and political insider intuition that statewide results for presidential and/or governor tend to flip partisan control before state legislatures flip partisan control. SDAN could not find existing research to substantiate (or refute) that intuition, so we compiled the data to investigate those claims. 

If industry intuition is true, and state chambers only flip partisan control after statewide/presidential races flip, this may have implications for where organizations and volunteers should be spending their time and money. It may also affect which states operatives should be targeting to flip and which states may require more of a consistent state-wide shift before a state legislature flip can be expected.

Methods: Subjects & Variables

Data Collection and Analysis

This is a non-experimental archival study exploring data collected by SDAN from Secretaries of State in all U.S. states, as well as from additional sources like Ballotpedia and Wikipedia. The dataset included all state legislative, U.S. Senate, gubernatorial, and presidential elections held in even-year election years since 2000 and included either the election winner or, in cases where an election was not held in that chamber or for that position that year, the party controlling the seat at that time. 

All of the a priori hypotheses concerned the most recent period of redistricting (2011-2020), as the REDMAP operation in the 2010 elections allowed Republicans to flip far more state legislative chambers than Democrats, which had a reverberating effect on the elections throughout the 2011-2020 period. 

However, since the dataset was complete through 2001, some exploratory hypotheses took advantage of the whole dataset. This larger dataset allowed explorations of the last two rounds of congressional and state legislative redistricting, as well as multiple rounds of all types of elections included in the analyses, to provide a more generalizable baseline.

For both the primary and exploratory hypotheses, data were analyzed descriptively and conclusions were drawn from patterns observed in the data.

All of the tables and data referred to in this report can be found at this link.

Important definitions

State legislative chamber flips. A state legislative chamber was considered a flip if it changed party control from one political party to another. Flips were measured as of the election the partisan change was voted in (as opposed to the year the partisan shift in power actually occurred in states where it is the year following the election). Only the most recent flip from  2011-2020 was used in the 2011-2020 chamber flip analyses. Only the most recent flip from 2001-2010 was used in the 2001-2010 chamber flip analyses. Chamber flip analyses from 2001-2020 include the most recent chamber flips in states from 2001-2020. The dataset included data from the years 2000-2020.

Trifecta status. A trifecta is a state with a single party in charge of both chambers of the state legislature and the Governor’s seat. Trifecta status was measured as of the election the partisan change was voted in (as opposed to the year the partisan shift in power actually occurred in states where it is the year following the election). Only the most recent trifecta status was used. The dataset included data from the years 2011-2020. Trifecta status was included if it was achieved at any time during the 2011-2020 period, even if the state lost trifecta status in that same period.

Please note that, in cases where the last US Senate vote is referenced, it is referencing the most recent vote for either of that state’s US Senate seats. Also note that when we refer to votes for President, Governor, or US Senate in the previous election for states with chamber flips, it does not indicate that the votes for President, Governor, or US Senate flipped in the previous election. Votes for these higher level offices often flipped years or even decades before state legislative chambers in some cases. 

Results: Descriptive Analyses

Results: 2011-2020

Presidential voting and state legislative flips 

There were 17 states where at least one chamber flipped between 2011-2020. Of those states, that flip was preceded by the state flipping its vote to that party’s presidential candidate 88.24% of the time. Alaska, Arkansas, Iowa, Kentucky, Louisiana, Mississippi, New Hampshire, and West Virginia all flipped at least one state legislative chamber red during this period, preceded by having flipped its vote to a Republican presidential candidate 75% of the time (Iowa’s presidential vote flipped the same year as its state senate and New Hampshire has voted for the Democratic presidential candidate since 2004). 

100% of the states that flipped at least one state legislative chamber blue during this period (Colorado, Maine, Minnesota, Nevada, New Mexico, New York, Oregon, Virginia, Washington) had already flipped the state’s vote to the Democratic candidate for president.

For 20 of 23 states that formed trifecta status at any point in the 2011-2020 period², that status was preceded by the state having flipped its vote to that party’s presidential candidate 86.96% of the time. This pattern was especially evident for blue trifectas, 100% of which formed after the state voted for the trifecta party’s presidential candidate. It was somewhat less likely for red trifectas, 72.73% of which were preceded by the state voting for the Republican presidential candidate in the previous election. 

Additional exploration beyond the planned hypotheses indicates that Democrats take a longer time to flip state legislative chambers after the presidential vote flips than Republicans. Red presidential flips happened a median of 14 years (average of 18.29) before a state legislative chamber flips red (n = 6) compared with a median of 24 years (average of 22.33) between when a state flips its presidential vote blue and when a state legislative chamber flips blue (n = 7). For example, there were 46 years between when Minnesota started voting for the Democratic presidential nominee (since 1972) and flipping the state house in 2018. This pattern indicates that blue state legislative flips take about 1-2 more presidential cycles to flip the state legislature compared to red flips. 

Gubernatorial voting and state legislative flips

Of the 17 states where at least one chamber flipped between 2011-2020, 64.71% (11) voted for the party’s gubernatorial candidate in the previous election. 

Of the states that gained trifecta status from 2011-2020 (whether they remained trifectas or not), only 12 of 23 elected a governor from the trifecta-controlling party the cycle before reaching trifecta status. In 11 cases, electing a governor (or a sitting Governor switching party affiliation) was the event that triggered the trifecta. This means that Governors being elected or switching parties was essentially just as likely to be the reason a trifecta was achieved as flipping the state legislative chambers (13/23 instances – one instance involved governor and state legislature flips in the same year and was counted for both). 

Overall, this hypothesis was not well supported, with 52.17% of those newly formed trifecta states electing a Governor from the trifecta-making party the election before the trifecta is formed. This result is very close to chance (50%). It was slightly more likely for Republican trifectas to elect a Republican governor before the trifecta was formed (54.55%) compared to Democratic trifectas electing a Democratic governor first (50%). Interestingly, Democratic trifectas formed during this period were more likely to still be trifectas in 2020 compared to Republican trifectas (91.67% compared to 63.64%). See table 2 for more information.

H12 – Democrats flip at the gubernatorial level for a longer time before the state legislature flips, compared to Republicans, who have a lower average time to flip. 

This analysis considers years from a governor flip to the most recent state legislative chamber flip in a state after 2011. Whichever party most recently flipped the state legislative chamber was also considered the party to measure for governor flips. 

This hypothesis appears to have support. Blue state legislative flips happened a median of 8 years after the governor’s seat flipped. Red state legislative flips happened a median of 4 years after the governor’s seat flipped. This indicates that blue state legislative flips take 1-2 more governor’s cycles compared to red flips. See table 9 for more information.

US Senate voting and state legislative flips

H1 – For any state legislative chamber that flipped party control in the years 2011-2020, this flip was preceded by a statewide vote for that party’s U.S. Senate candidate. 

This hypothesis was evaluated by looking at states where at least one state legislative chamber flipped from one major party’s control to the other between 2011-2020. For bodies where only 1 chamber flipped in the 2011-2020 period, the other body either appears greyed out (if it was in the dataset) or with a dash (if it was before the time the dataset began – 2001 for state legislatures).There were 17 states where at least one chamber flipped between 2011-2020. Of those states, 76.47% first voted for that party’s U.S. Senate candidate. See table 1 for more information.

H5 – For any state that gained trifecta status between 2011-2020, this status was preceded by a vote for that party’s US Senate candidate.

Interestingly, we see a similar level of support for this hypothesis as we did for whether votes for presidential candidates from the trifecta-forming party lead to state legislative chamber flips. We found that 86.96% of the time, a state voted for US Senate candidates of the trifecta-controlling party before the trifecta was formed. It was about 10% more prevalent for Democratic trifectas (91.67%) than for Republican trifectas (81.82%), but it was high for both parties. See table 5 for more information.

Sequences:

H4 – Building partisan power in a state tends to follow a specific sequence: partisan control first flips at the presidential level, then the gubernatorial level, and finally, state legislative control of one or both chambers flips.

This hypothesized sequence does not have support. Gubernatorial races were the weakest indication of the statewide offices investigated of flips in the state legislature and only foreshadowed trifecta status 52.17% of the time from 2011-2020, which is close to the level of chance. In the states that saw at least one chamber flip from 2011-2020, only 41.18% of states follow this full sequence. The incidence was even lower for states with flips in the 2001-2010 period, where this sequence was only seen 20.69% of the time. See tables 4 and 14.

As an exploratory hypothesis, we investigated whether the presidential, then gubernatorial, then state legislative flip sequence existed in states that became trifectas after the state legislature flipped.  It appears that 50% of the states that became trifectas from 2011-2020 followed the sequence of first flipping the presidential vote, then the governor’s vote, then the state legislature. This is not particularly strong evidence (6 races out of 12 is the level of chance). It also appears to be equally prevalent among red trifectas and blue trifectas that were formed in the 2011-2020 period, with 50% of each type following the sequence. See table 4 for more information.

Exploratory Hypotheses:

H6 – Building partisan power in a state tends to follow a specific sequence: partisan control first flips at the presidential level, then for a US Senate candidate, and then finally state legislative control of one or both chambers flips such that a trifecta is formed.

This sequence is only followed 39.13% of the time. Further, there do not appear to be major partisan differences, with Democratic trifectas following the sequence 41.67% of the time and Republican trifectas following the sequence 36.36%. See table 6E.

An exploratory model echoing the model from H4E was also used in H6E, focusing only on states that became trifectas after one or more state legislative chambers flipped. 

H6E – Building partisan power in a state tends to follow a specific sequence: partisan control first flips at the presidential level, then for a US Senate candidate, and then finally, state legislative control of one or both chambers flips such that a trifecta is formed, in states that formed trifectas after a state legislature (as opposed to a gubernatorial) flip.

This sequence held 66.67% of the time in states that became trifectas when the state legislature flipped. It was more likely to occur in Democratic trifectas (83.33%) than in Republican trifectas (50%). This may indicate that votes for US Senator may be a more reliable indicator of gaining blue than red trifecta status. See table 6E for more information.

H7 – The pattern in H6 also holds for entire US Senate delegations (both US Senate seats in a state) such that voters flip their presidential preferences and then vote for both US Senate candidates of the eventual trifecta party before flipping state legislative control of one or both chambers flips such that a trifecta is formed.

As seen in the chart for H5 (Table 5), there is mixed support for this hypothesis. Across all states that became trifectas from 2011-2020, only 43.48% had a full US Senate delegation from the trifecta party before the trifecta-making election. However, this was the case more for Democratic trifectas, with the full US Senate delegation being Democratic before a majority (8) of Blue trifectas were formed (66.67%; n = 12) and only 2 of the Red trifectas (18.18%; n = 11). These findings may indicate that Democratic trifectas are formed differently than Republican trifectas and have different antecedents.

H8 – Gerrymandered states that become trifectas will see a short gap between their state flipping their presidential vote and flipping their state legislature.

According to the Brennan Center, just 7 states account for most of the partisan bias seen in the districting process that leads to the overrepresentation of the gerrymandering party relative to its vote share. These states (FL, MI, NC, OH, PA, TX, VA) had new³ 2011 state legislative maps drawn under a Republican-controlled state legislature (all states but VA) or a split legislature and a Republican governor (VA). Throughout the period considered in this analysis, only TX and VA follow the trend of voting for the majority party for president before attaining a majority for that party in at least one state legislative chamber.

Texas had a long-established record of voting for Republican presidential candidates before flipping the most recent state legislative chamber (22 years). To a lesser but still consistent degree, Virginia had been reliably voting blue for president for 11 years before flipping the state legislature in 2019 (though the house of delegates flipped back as of 2021). The other states saw either a flip in the legislature first and then saw the presidential selection flip somewhat consistently (NC) or a flip in the state legislature, and then a repeated back and forth at the national level for president (OH and FL). 

Interestingly, the remaining 2 states, MI and PA, both voted for Biden in 2020 and already had Democratic governors despite Republicans retaining a majority in both state legislative chambers. Further, Michigan has a full Democratic US Senate delegation, and Pennsylvania currently has a split US Senate delegation, with the last US Senate vote in 2018 going to a Democrat. These may be prime state legislatures to flip as, except for the 2016 election, both states have voted blue for president for more than 20 years. The evidence for gerrymandering in these two states affecting the partisanship in the state chambers is the strongest of these 7 most gerrymandered states. It reflects critical encroachment on the will of the people. See table 7 for more information.

H9 – Sequence trends differ in red and blue trifectas such that blue trifectas follow a flip sequence (e.g., president -> US Senate -> state legislature) more often than red trifectas.

This hypothesis is addressed at the bottom of the tables for H4 and H6E (Tables 4 and 6E). For the flip sequence president -> governor -> state legislature in states that became trifectas after flipping the state legislature (as opposed to the governorship), this did not appear to be a pattern for either party, with only 50% of both types of trifectas demonstrating this sequence. 

Democratic trifectas formed by flipping state legislative chambers, on the other hand, do follow the flip sequence, president -> at least one US Senate seat -> state legislature, more than Republican ones. 83.33% of blue trifectas followed the sequence compared to 50% of red trifectas. When we looked at the entire US Senate delegation in H7, there were stark differences between the parties: 66.67% of blue trifectas elected two Democratic US senators prior to flipping the state legislature, compared with only 18.18% of red trifectas electing two Republican US senators. The data provides mixed evidence for H9 and suggests that statewide non-presidential federal races may be a better bellwether for blue trifectas than statewide state races like Governor. Further, neither sequence (president > at least one US Senator > state leg, or president > whole US Senate delegation > state legislature) seems to be a reliable bellwether for red trifectas, nor does it appear to be a reliable sequence for trifectas that form after a Gubernatorial flip.

Other Hypotheses Explored:

H10 – Trifectas are formed more in presidential years than in midterm years.

This hypothesis did not have robust support. Of the 23 trifectas formed in the 2011-2020 period, 9 were formed in presidential years (AK, IA, KY, MN, MO, MT, NH, NC, OR), 7 formed in congressional midterm years (AR, CO, IL, ME, NV, NM, NY), and the remaining 7 formed during odd-year elections (LA, MS, NJ, VA, WA) or by a sitting governor switching party affiliations (RI, WV). This indicates that trifectas were formed more often in presidential election years recently, but midterm election years are also strong trifecta-makers. More needs to be known about historical trends, as the bulk of midterm flips happened in 2018 as a potential referendum on the Trump presidency. Since the Trump presidency is unprecedented in the modern era, it is necessary to investigate elections in midterms unaffected by Trump. See Table 3.

2001-2020 results

H11b – In states that saw a chamber flip since 2001, blue state legislative chamber flips are preceded by larger margins for the Democratic presidential candidate in the previous election than red chamber flips margins for Republicans.

This hypothesis does not have support. Among states that saw chamber flips during 2001-2010, the last 2-way presidential margins (D-R) had a median of 9.5%. In the 2011-2020 period, this median increased to 12.54% (the entire 19-year period saw a median of 11.86%).

From 2001-2010, Democratic margins in states that saw blue chamber flips had a median of 11%, while the margin in states that saw a red chamber flip was 5%. From 2011-2020, these figures swapped, with Democratic chamber flip states seeing presidential margins at a median of 6.68% and Republican chamber flip states seeing presidential margins at a median of 19.25%. This demonstrates that presidential candidates are seeing tighter average presidential numbers in Democratic chamber flip states that have seen a state legislative chamber flip over the past decade than they were enjoying the decade prior. Interestingly, Republican states see wider presidential margins than Democratic candidates in these chambers. These wider margins indicate that H11b does not have support, and it is actually Democrats seeing smaller margins pre-flip than Republicans. However, interestingly, in several Republican-controlled swing states (IA, IN, MI, NH, NC, OH, PA, & WI), the presidential margin immediately preceding the flip reflects a margin for the Democratic presidential candidate. This may explain why Republican states have a smaller margin; swing states that vote for different parties at different levels generally see smaller margins than safe blue or red states.

Among states that have not seen a state chamber flip since 2001, their 2008 margins⁴ suggest a median winning margin of 15.13% for the state’s presidential winner. This shows that states where state legislative chambers flip tend to see tighter presidential race margins than states where state legislative chambers don’t flip, at least in the past 10 years. This is the opposite of H11a when considering the past 20 years. Please note that for states with multiple presidential race margins listed, the most recent margin was used for calculations. See tables 8 and 13 for more information.

H13 – These trends hold as far back as 2001.

With regard to governors’ serving as an antecedent to chamber flips, this hypothesis is not supported. According to Table 10, 41.67% of states that flipped at least one chamber in the 2000-2020 period first elected a governor of the party that later flipped the legislature. This means that H1 doesn’t hold for the 20-year outlook for governors’ votes predicting state legislative votes. 

The trend does hold with regard to Presidential vote as an antecedent to flipping a chamber. Of states that flipped at least one chamber in the same period, 77.78% first elected a presidential candidate of the same party. This indicates that H1 is true in most states when it comes to presidential voting. Interestingly, the 2001-2010 states that flipped at least one chamber elected a presidential candidate of the same party 55.17% of the time – much lower than the 88.24% we saw in the 2011-2020 period. But it was still a strong indicator for Democratic flips, predicting Democratic flips 70% of the time to Republican flips 47.37% of the time.

The trend has some support with regard to Senate vote as an antecedent to flipping a chamber. 63.89% of states that flipped at least one chamber from 2001-2020 elected a US Senator of the same party in the prior election first. This is weaker than the findings about trifectas but still demonstrates an almost 64% prevalence of US Senate seats flipping before state legislatures. Further, among states with Democratic chamber flips, this prevalence was 76.92% compared to Republicans’ 54.17%, confirming findings from H5 in a longer time period. See table 11 for more information.

2001-2010 results

Spotlight Results

1. Presidential and Senate races appear to reliably foreshadow state legislative flips, especially for Democrats

 Presidential votes in states tend to flip parties before at least one chamber of the state legislature does. Between 2011-2020, this pattern occurred 88.24% of the time. Between 2001-2010, the pattern occurred 55.17% of the time (47.37% of the time for Republican flips and 70% for Democratic flips). Between 2000-2020, the pattern occurred 77.78% of the time (100% of the time for Democratic state legislative flips and 65.2% for Republican state legislative flips).

These proportions suggest that the sequence is a more reliable indicator for Democratic power-building than for Republican power-building. 

US Senate candidates also appear to reliably flip before state legislative chambers. Said another way, it is reliably the case that, when a state legislative chamber flips, that party already has at least one US Senator of that party. Between 2011-2020, this pattern occurred 76.47% of the time. Between 2001-2010, the pattern only occurred 48.28% of the time. Between 2000-2020, the pattern occurred 63.89% of the time.

The sequence of US Senate seats flipping before state legislative chambers in states that become trifectas is a slightly more reliable indicator for Democratic power-building than Republican power-building, and it appears to have become a better signal over time. Between 2011-2020, the sequence occurred 91.67% of the time for Democratic trifectas and 81.82% of the time for Republican trifectas. See tables 1,10, and 14.

2. No evidence of Pres > Gub > full state leg flip sequence in trifecta states

Interestingly, there was no evidence for the trifecta making sequence of presidential vote, then gubernatorial, then state legislature. When looking just at states that became trifectas due to a state legislative flip alone (n = 12), it appears that 50% (n = 6) flipped along the sequence president, then Governor, then state legislature. But this figure is the level of chance. 

3. Some evidence of Pres > US Senate > full state leg flip sequence in trifecta states

However, there does appear to be a possible sequence for presidential vote, then US senate, then state legislature, with 66.67% of trifectas that formed after a state legislative chamber flipped saw a US senate seat flip first (though the rate is only 39.13% when including states that became trifectas after gubernatorial flips). This sequence appears to be more reliable in predicting blue flips than red. In the 2011-2020 period, Democratic trifectas flipped their entire US Senate delegation 66.67% of the time before flipping their state legislature compared to Republican trifectas flipping their entire US Senate delegation 18.18% of the time. 

Conclusions, Limitations, and Future Research

There was strong evidence that most states that see chamber flips or trifecta status see their presidential votes flip first. It also appears that US Senate party control may flip fairly reliably before state legislatures. These two sequences are especially strong indicators for Democratic state chamber flips. 

In particular, we found strong supporting evidence for the notion that state legislative chambers typically rarely flip before the state votes for that party’s presidential candidate in the prior election. In most state legislative chambers that flipped from 2011-2020, states first voted for a president of that party. It was also more reliable for Democratic flips (100%) than Republican ones (72.73%).

This study was limited in several ways, including the fact that this was archival research and cannot support causal claims. Further, it was limited in scope, as there are only 99 state legislative chambers in the country. The dataset used also only went back to 2001, which only spans 5 presidential elections, and most analyses only included the period of 2011-2020. This restricted our sample size and made some analyses difficult to perform due to the small portion of the population that met criteria (for instance, for trifectas formed after state legislative flips). 

In the future, more states that become trifectas should be added to the dataset over the next decade to determine if these trends hold with trifectas formed during the 2020s. Further, it may be interesting to compare these trends to trends in states that have split government, as these are often the states that concern political pundits as “battlegrounds.” It would also be educational to investigate the antecedents to losing trifecta status, as this would be just as useful in forecasting changes in state party leadership as antecedents to forming trifectas. The length of time between the presidential or gubernatorial flip should also be investigated further. Finally, there should be some effort to remove flips that reflect a correction (like Southern states flipping D to R) and flips that reflect changes in actual voter behavior. This would help to clarify the margins in states where gerrymandering has occurred and isolate them from states where voters are simply more homogenous.

¹ The presidential choice for each year was recorded as the party the state voted for in the most recent presidential election. For non-presidential even-numbered election years (2002, 2006, 2010, 2014, and 2018), that choice was the party of the candidate the state voted for for president in 2000 (2002), 2004 (2006), 2008 (2010), 2012 (2014), and 2016 (2018).

² Oregon, Minnesota, Rhode Island, Washington, New Jersey, Nevada, New York, New Mexico, Maine, Illinois, Colorado, and Virginia all gained blue trifecta status at some point in the 2011-2020 period. Louisiana, Mississippi, North Carolina, Alaska, Arkansas, Kentucky, Iowa, Missouri, West Virginia, New Hampshire, and Montana all gained red trifecta status at some point in the same period.

³ All U.S. states redrew their state legislative district maps in 2011, but some states, like North Carolina, Virginia, and Florida, have redrawn or partially redrawn their state legislative maps more recently due to court orders. These map changes are not accounted for in the consideration of the data due to the introduction of additional variables/shortened available timeline for these battleground states/the fact that data is presented in aggregate.

⁴ The margin for the 2008 presidential election margin was pulled for states that did not see state legislative chamber flips in the last 20 years in order to allow the inclusion of all U.S. states in Table 8. The 2008 election was chosen for states that did not flip because it was close to the middle of the dataset and did not involve a sitting president with incumbent advantage.