Congressional Incumbents in Opposite Double-Digit Presidential Party-won Seats from 2008-2020

Author's Note: I know, the title of this post is overly long and complicated, but I couldn't think of anything better.

Congressional Incumbents in Opposite Double-Digit Presidential Party-won Seats from 2008-2020

Introduction: In May, I uploaded a post detailing the number of Congressional incumbents who lost by double-digits from 2010 through 2020. One of the main results that came out of that post's analysis was the massive post-2010 decrease in Congressional incumbents losing by double-digits, which I attributed to be the result of increasing polarization, straight-ticketing, and partisan inclinations to focus on seats voting near the median. Today's post will be a sibling of that post as it will look at the number of incumbents holding seats whose area provided a double-digit margin to the past opposite presidential candidate. As we will see, some of the same results and implications will be repeated from the earlier post, as a similar story and timeline is told using this electoral metric.

Methodology: Data sources are listed below, with bullet points under each indicating what specific information or data each source provided for this post. Data for 2012, 2014, 2016, 2018, and 2020 House district results were transcribed from existing secondary sources compiling such data, while data on 2010 and 2008 was self-determined by comparing House election results from the U.S. House of Representatives Clerk to 2008 presidential results from the Swing State Project. A similar process was done for determining which Senators occupied opposite presidential party double-digit states for each year using election results from The American Presidency Project at UCSB and Congressional biographies listing years of service.

Table 1: Congressional Incumbents in Seats Voting for the Opposite Presidential Candidate by Double-Digits

Notes: The values per column take into account member affiliation at the time when each new Congress opened after the listed election cycle. Therefore, any mid-Congress party switches (e.g. Sen. Arlen Specter in 2009) or seat flips due to special elections (e.g. Sen. Doug Jones in 2017) are reflected in the next cycle's numbers unless they were no longer seated at the time, and the same goes for any members affected by mid-cycle redistricting. Independents and third-party members are not listed unless they were not caucusing with a majority party and won an election under that status (i.e. ex-Rep. Justin Amash is not included, as he retired after changing his party status). For midterm years (i.e. 2010, 2014, 2018), the most recent presidential results were used as the benchmark, while for 2008, 2012, 2016, and 2020, that year's presidential results were used. 

Results and Analysis:

• 2008: Coming off of the broad Democratic Congressional gains of 2006 and 2008, 24 Democratic Representatives and 7 Senators represented seats that voted for 2008 Republican presidential candidate John McCain (R) by over 10%. Despite the South already voting red in the presidential election, a sizable group of Democratic representatives held seats in largely non-urban and majority-White areas in that region, plus others in the Midwest and several in the West. On the other hand, there still existed 7 Republican Representatives and 4 Republican Senators holding seats that voted for Obama by double-digits, including Senator Arlen Specter (R), who switched his party affiliation in mid-2009 (Nasaw). 2008's results are notable due to the extreme variation in presidential election results relative to House members' seats, as the most pro-McCain-voting district held by a Democrat was Chet Edwards' TX-17 (35% margin for McCain) and most pro-Obama district held by a Republican was Joseph Cao's LA-2 (49% margin for Obama) (DavidNYC). Such a gap would shrink significantly with the 2010 House results, and especially after the 2014 House elections, when both Rep. Jim Matheson (D) from his 63% Romney seat and Gary Miller (D) from his 57% Obama seat retired. Both seats ended up flipping to the opposite party that November (Kondik, "The State", 78-79).
• 2010: In the 2010 midterms, Republicans won a net 63 House seats to flip back the lower chamber and a net 7 Senate seats that significantly carved into the Democratic majority. Almost all of the Democratic House incumbents holding double-digit McCain districts either retired or lost reelection bids, with only 6 remaining after 2010 (Mike Ross from AR-4, Ben Chandler from KY-6, Dan Boren from OK-2, Jason Altmire from PA-4, Jim Matheson from UT-2, and Nick Rahall from WV-3). And, it is worth noting that the six all faced close margins as well that year, with Chandler, Altmire, and Matheson coming close to losing (Cook; "Preview"). The extent of the Republican wave resulted in the party holding 16 double-digit Obama House seats, 6 of which were in Illinois, which is possibly a reflection of Obama's extremely good performance in his home state and the subsequent reversion in 2010 ("Illinois"). On the Senate side, only one Democratic incumbent in a double-digit McCain state, Sen. Blanche Lincoln (D), lost, but Republican candidates won seats in the double-digit Obama states of Illinois, Pennsylvania, and Wisconsin. 
• 2012: On the House side, redistricting, retirements, primary defeats, and general election losses led to a significant decrease in the number of House districts giving Romney or Obama double-digit margins and electing an opposite party's House candidate. It is notable that the two Republicans holding double-digit Obama seats after 2012 were from California, one of whom, Rep. David Valadao of CA-21, had a unique appeal in a majority-Latino blue district, while the other, Rep. Gary Miller of CA-31, only won because he and another Republican locked Democratic candidates out of the general election due to California's "Top 2" primary. On the other hand, of the 4 Democratic members holding double-digit Romney districts, all were survivors who had made it through the 2010 wave year, but faced tough races in 2012 (Kondik, "Hard Targets?"). That year's Senate elections saw Democrats perform quite well despite the map being against them, thus increasing their number of Senators in double-digit Republican presidential states compared to 2008 (Rothenberg). However, keep in mind that a key bloc in that group had last faced voters in 2008, prior to the Republican wave, thus making them vulnerable going into the next cycle, as we will see below. 
• 2014: Like the 2010 wave, the 2014 red wave saw Democratic districts with a variety of 2012 presidential voting patterns flip red, which included all four Democratic incumbents in double-digit Romney-won seats retiring or losing to Republican candidates. Yet, multiple double-digit Obama-won districts also flipped red that year, with the most notable being Rep. John Katko (R)'s defeat of incumbent Rep. Dan Maffei (D) by over 13% in a seat Obama had won by 16%! Two perennial swing districts explored earlier this year, IA-1 and NV-4, also flipped red despite voting for Obama by double-digits two years prior. On the Senate side, the retirements of multiple Democratic Senators in double-digit Romney states helped Republicans significantly reduce the number of Senators in that category, which was further increased by the defeats of Senators Mark Pyror (D-AR) and Mary Landrieu (D-LA) (Hohmann, 57-58, 63-64). As stated on the earlier post, the Republican takeover of the South's Congressional delegation was completed on Election Night 2014, although Democrats have seen some bounceback in the region since 2016. Furthermore, this became the most recent election cycle in which any Republican Senators represented states that voted for the past Democratic presidential candidate by double-digits.
• 2016: Partisan sorting around presidential results continued with Donald Trump (R)'s presidential victory and the good Republican performance in House and Senate races. Yet, some split-ticketing still occurred that altered the composition of double-digit seats voting for the opposite Congressional candidate. Two of the new double-digit Clinton districts were in South Florida, where Latino Republican incumbents cruised to victory even as their districts turned against Trump, while the third was Valadao (Kondik, "House 2018"). Note that some sources indicate that Rep. Barbara Comstock (R) of VA-10 won by exactly 10% ("House 2018"), although sources that use 2 decimal places (such as Daily Kos) indicate she won by just under 10% (Nir). With that in mind, I did not include her in the data above, although her position in holding such a district that Democratic made her extremely vulnerable going into 2018; VA-10 was the first Republican district with an incumbent that Sabato's Crystal Ball rated as a flip (Kondik, "A half-dozen"). Meanwhile, Donald Trump's unexpectedly-good performance in non-urban Minnesota led to three of its Democratic districts to vote for him by double-digits while their incumbents all narrowly survived (Kondik, "2016", 79). Likewise, the total number of Senators in states voting for the opposite party by double-digits did not change much either, except for Sen. Mark Kirk (R) losing to now-Sen. Tammy Duckworth (D) and the 2016 presidential results resulting in Republican Sen. Susan Collins (R) dropping off the list and Sen. Claire McCaskill (D) being added.
• 2018: Like the 2010 and 2014 Republican House waves, the 2018 Democratic wave was not just limited to Clinton-won and single-digit Trump districts, as Democratic candidates flipped several double-digit Trump-won districts (Kondik, "House 2020"). On the Senate side, the losses of Sens. Heidi Heitkamp (R-ND), Joe Donnelly (R-IN), and Claire McCaskill (R-MO) reduced the number of Democratic Senators in double-digit Trump states, although they were balanced-out by Sen. Doug Jones' (D-AL) surprise victory in the 2017 Special. No Republicans held any double-digit Clinton seats in Congress after 2018, and only three (not counted the projected numbers from North Carolina's 2020 redistricting) held Clinton-won seats, all three of whom narrowly won in 2018 (Kondik, "House 2020").
• 2020: The number of Congressional incumbents in seats that gave double-digits to the opposite presidential candidate reached its lowest point in 2020, with only 3 Representatives and 2 Senators falling into this category. Oddly like 2012, the three Representatives were all California Republicans who overperformed compared to Trump while netting narrow victories in largely- or majority-minority districts, including the successful comeback of Rep. David Valadao in CA-21 (R) (Kondik, "2020's"). On the Senate side, Joe Manchin (D-WV) and Jon Tester (D-MT) remain the only two Senators in double-digit Trump states. However, both are up for reelection in 2024, and preliminary discussion has already focused on whether either will be able to win again, especially considering that neither state shows any signs of becoming less red since Trump first came onto the scene (Rothenberg).

Conclusion: Repeating what I noted in the introduction, the decline in Congressional incumbents holding seats hat gave a double-digit margin to the opposite presidential candidate reflects increased political polarization and straight-ticket voting. Furthermore, this could also be a reflection on party campaign institutions increasingly focusing their efforts on seats whose area voted for the last presidential candidate by any amount close to zero percent. While partially dependent on presidential results, an interesting trend from Senate results is that until 2014, Senate Democrats still held a significant amount of seats in double-digit Romney states. Note that this is probably because 1) Senate seats never go through "redistricting," and 2) The aforementioned bloc of multiple Democratic Senators that had last faced reelection in 2008 (pre-realignment) and whose seats did not flip until 2014 because of how Senators have 6-year terms. The same can be said for the last two Senators holding seats that voted for Trump by double-digits, as both Manchin and Tester were lucky to have their reelection bids coincide with the relatively good years of 2012 and 2018, and that enough downballot ticket-splitting remained to help them both win in the latter. Yet, considering the extent of declining straight-ticketing in presidential years combined with their states' significant red lean, the aftermath of 2024 may be the first in a while in which no Senators occupy states that voted for the opposite presidential candidate by double-digits.

Election Data Sources:

DavidNYC. "Presidential Results by Congressional District, 2000-2008." Swing State Project, 15 Dec. 2008, swingstateproject.com/diary/4161/presidential-results-by-congressional-district-20002008. Accessed 18 Sept. 2021. 

• 2008 Presidential results by House district

"Election Listing" The American Presidency Project, University of California, Santa Barbara, www.presidency.ucsb.edu/statistics/elections. Accessed 18 Sept. 2021.

• 2008-2020 Presidential election results by state

"Election Statistics: 1920 to Present." History, Art, and Archives, United States House of Representatives, history.house.gov/Institution/Election-Statistics/. Accessed 18 Sept. 2021. 

• 2008 and 2010 House election results

Kondik, Kyle. "2020’s Crossover Districts." Sabato's Crystal Ball, 4 Feb. 2021, centerforpolitics.org/crystalball/articles/2020s-crossover-districts/. Accessed 18 Sept. 2021.

• Post-2020 House-President crossover districts

---. "Hard targets?" Sabato's Crystal Ball, 4 Apr. 2013, centerforpolitics.org/crystalball/articles/hard-targets/. Accessed 18 Sept. 2021.

• Post-2012 House-President crossover districts

---. "House 2018: Crossover appeal." Sabato's Crystal Ball, 9 Feb. 2017, centerforpolitics.org/crystalball/articles/house-2018-crossover-appeal/. Accessed 18 Sept. 2021.

• Post-2016 House-President crossover districts

---. "House 2020: The new crossover districts." Sabato's Crystal Ball, 29 Nov. 2018, centerforpolitics.org/crystalball/articles/house-2020-the-new-crossover-districts/. Accessed 18 Sept. 2021.

• Post-2018 House-President crossover districts

---. "The State of the House." The Surge, edited by Kyle Kondik, Larry J. Sabato, and Geoffrey Skelley, Rowman and Littlefield, 2015, pp. 73-85. 

• Post-2014 House-President crossover districts

Kondik, Kyle, Larry J. Sabato, and Geoffrey Skelley, editors. The Surge: 2014's Big GOP Win and What It Means for the Next Presidential Election. Rowman and Littlefield, 2015. 

"Members of the U.S. Congress." United States Congress, www.congress.gov/members?pageSize=100. Accessed 19 Sept. 2021.

• Used to determine which Senators were seated in each Congress (i.e. following each election cycle); compared this to the presidential election results to determine which Senators represented states that voted by double-digits for the opposite presidential candidate.

Works Cited: 

Cook, Rhodes. "2010 HOUSE RESULTS: A PORTENT OF INCREASED COMPETITION?" Sabato's Crystal Ball, 21 Dec. 2010, centerforpolitics.org/crystalball/articles/frc2010122101/. Accessed 19 Sept. 2021.

Hohmann, James. "The 2014 Senate Elections --- and Beyond" The Surge, edited by Kyle Kondik, Larry J. Sabato, and Geoffrey Skelley, Rowman and Littlefield, 2015, pp. 53-72.

"Illinois - Election Results 2010" The New York Times, www.nytimes.com/elections/2010/results/illinois.html. Accessed 19 Sept. 2021.

Kondik, Kyle, Larry J. Sabato, and Geoffrey Skelley, editors. The Surge: 2014's Big GOP Win and What It Means for the Next Presidential Election. Rowman and Littlefield, 2015. 

---. Trumped: The 2016 Election that Broke all the Rules. Rowman and Littlefield, 2017. 

Kondik, Kyle. "2016 House: The Republicans Endure." Trumped, edited by Kyle Kondik, Larry J. Sabato, and Geoffrey Skelley, Rowman and Littlefield, 2017, pp. 70-82. 

---. "A half-dozen House ratings changes in favor of Democrats." Sabato's Crystal Ball, 28 Jun. 2021, centerforpolitics.org/crystalball/articles/17816/. Accessed 19 Sept. 2021.

Nasaw, Daniel. "Pennsylvania senator Arlen Specter switches party to become Democrat." The Guardian, 28 Apr. 2009, www.theguardian.com/world/2009/apr/28/arlen-specter-republican-democrat-senate. Accessed 19 Sept. 2021.

Nir, David. "Daily Kos Elections' presidential results by congressional district for 2020, 2016, and 2012." Daily Kos, 19 Nov. 2020, www.dailykos.com/stories/2020/11/19/1163009/-Daily-Kos-Elections-presidential-results-by-congressional-district-for-2020-2016-and-2012. Accessed 19 Sept. 2021. 

"Preview of Key House Races." The New York Times, www.nytimes.com/elections/2010/results/house/preview.html. Accessed 19 Sept. 2021.

Rothenberg, Stuart. "The Democrats’ 2024 Senate problem." Roll Call, 18 May 2021, www.rollcall.com/2021/05/18/the-democrats-2024-senate-problem/. Accessed 19 Sept. 2021.

"Statistics of the Congressional Election of November 2, 2010." Clerk of the United States House of Representatives Karen L. Haas, 3 Jun. 2011, history.house.gov/Institution/Election-Statistics/. Accessed 19 Sept. 2021.

     Nathan Parmeter

     Author and Host, The Parmeter Politics and Policy Record