The Congressional Race Over Time

Congress and the Harris Effect

There is clearly a lot of attention focused on what is happening at the top of the ticket this year, but the Presidential race is not the only game in town. The GOP currently has an incredibly small majority in the House of Representatives. In this Congress, there are 220 Republican members, 211 Democratic, and four (4) open seats. Democrats would need to hold the three (3) open seats that were previously occupied by a member of their party and then win four (4) additional seats to retake the majority that they lost in 2022. National numbers are not overly predictive when it comes to how many seats a party will likely win; however, these numbers do give a sense of the overall direction an election is likely to head in. A big lead in the national numbers points to a good night for that party, while a close national race tends to predict a smaller number of seats switching parties.

Political races tend to not function in a vacuum, and in a year where there have been so many seismic events at the presidential level, it is fascinating to see how these changes affect downstream numbers. One of our standard questions is asking Americans who they would likely vote for at the Congressional level. Because arguably 90% of Americans live in a district where the outcome is nearly a given, we do not use this question to predict specific wins or losses but to gauge the political mood of the country.

Looking back in time to May of 2023, we find that Republicans tended to hold the advantage for the second half of last year. Support for Democrats increased through the last four months of the year, and the two parties swapped the top spot on multiple occasions through the first six months of 2024. After Biden’s disastrous debate in late June this year, support for Republicans at the Congressional level increased and the GOP was able to put a decent amount of daylight between themselves and the Democratic party. This lasted for less than a month; once Harris became the presumptive nominee, support for the Democratic candidate steadily increased. In mid-August, Democrats took the top spot with very little room between the two parties.

September has been a good month so far for Congressional Democrats with an increase in support coupled with a slight downturn for Republicans. Further, the debate between Harris and Trump has increased this separation so far. When we overlay the numbers for the Congressional race along with the Presidential numbers starting on July 21 (when Harris was seeming likely to become the nominee), we can see how her increase in support is having an overall benefit to Democrats at the Congressional level. For Republicans, they are performing better than Trump, but his candidacy is clearly affecting their numbers in Congress.

Gender

While these overall numbers paint an interesting picture, when we dive into some of the demographic subgroups, it becomes arguably even more interesting. Gender and age cohorts have some of the most interesting differences and changes. Among women, Democrats have had a clear advantage going back to late spring of 2023. Average support for the Democratic candidate held relatively steady for over a year, as did support for the Republican candidate. Once Harris became the likely nominee, support levels steadily increased, as did support for the Republican candidate, running in roughly parallel lines.

Since Harris became the presumptive nominee, she has been running slightly ahead of the generic Congressional Democrat, while the generic Republican candidate has consistently been ahead of Trump. The biggest change in dynamic on the Democratic side came right around the time of the Democratic convention when Harris put a relatively large amount of daylight between herself and the generic Congressional candidate.

Men historically have been more supportive of Republican candidates and that continues to be the case. However, it is interesting to see a more typical gap in the Congressional data (about 6 points) while the gap between Trump and Harris is less than half of that number among men (2.7 points on average). Since Biden stepped down as the Democratic nominee, men have been slowly increasing their support for the generic Democrat while support for the generic Republican has remained relatively steady.

Another consistency has been the Congressional Republican outperforming Trump among men. On the other side of the aisle, the higher support has fluctuated. Harris had a slight edge from the time she became the presumptive nominee through the start of the Democratic convention. Through early September, there was very little difference between the Congressional Democrat and Harris - that is, until Labor Day weekend when Harris’s support increased a little faster and has continued on the same trajectory. During the same period, support for the Democratic congressional candidate held steady, creating a sustained gap.

Age

Age groups are also showing some very interesting (and unexpected) differences, at least in one particular age group. This election will mark the rough middle point for Gen Z to be able to vote. This is significant for two reasons. First, Gen Z and Millennials together will likely make up the largest voting bloc this election, and according to CIRCLE, Gen Z had the highest voting rate in first elections compared to other generations. Whether this trend continues will be determined in November; however, if the pattern holds, it appears it will be good news for Harris and Congressional Democrats.

The generic Democrat has been in the lead since May of 2023 among voters under the age of 45. Although the gap was relatively close earlier this summer, once Harris became the likely nominee, support for Democrats started to rise and has held that upward trajectory since. At the same time, the Republican candidate dropped slightly but has been holding relatively steady since the middle of August. Interestingly, the Congressional Democrat is outperforming Harris, while Trump is higher than the Republican candidate. In general, the Democratic candidate and Harris move at roughly the same levels, while Trump and the Republican candidate are less connected.

Gen X and younger Boomers are keeping it interesting. The Congressional Republican e has held the lead over the past 14 months among 45- to 64-year-old voters, running in mainly parallel lines over this time period. Unlike other cohorts, the switch from Biden to Harris on the Democratic side did not have a measurable influence on the Congressional numbers among members of this age group. However, Harris has been slowly growing her level of support while Trump’s support has remained relatively steady.

Currently, the Congressional Republicans have the highest level of support among this cohort, followed by Harris, then Trump, and then the Congressional Democrat. The delta between Harris and her party is about two points, while the difference between Trump and Republicans is just under three points (2.08 vs. 2.93 respectively). This is not a big difference but could be an indicator of movement in the future.

The last age group is arguably the most interesting. Support for the Congressional Republican was right around 50% at the beginning of the 4th quarter last year, and while it is down slightly from that level the average support has been relatively consistent. Since early this year, support for the Democratic candidate has been slowly increasing (about 5 points over the last six months) but still lags behind their Republican opponents. Trump’s support has also been holding steady since Harris entered the race although it’s been slipping since early September.

Harris, on the other hand, has been steadily ticking up and she has been receiving the highest level of support since late July. The Congressional Republicans, and Trump, were closing the gap through August but September has been heading in the opposite direction. That being said, there is not a clear pattern in how the support levels are changing when looking at different demographic groups. For Democrats, Harris is running stronger than the Congressional Democrat except among Gen Z and Millennial voters. For the GOP, the pattern is clear: except for voters under the age of 45, Trump is more of an anchor than providing wind in the sails. But, as discussed, the under 45 voting bloc will likely be a critical one.

Six weeks can be a lifetime in politics, but, so far, September has been a better month for Democrats than Republicans. While this does not mean the pattern will continue, it will certainly be interesting to watch in the next few weeks.

If you would like to look at the data and how it changes over time, we set up an interactive dashboard here: https://www.trendency.com/journal/the-2024-congressional-horse-race-over-time