What we know about the 2024 Democratic and Republican parties: An analysis of congressional candidates

In 2014, Brookings began studying all the candidates running for Congress through The Primaries Project. Unlike many studies of congressional elections in political science and unlike most journalists’ coverage of congressional elections, the Brookings studies focused on all candidates who got themselves on the primary ballot, whether they were serious challengers in competitive races or dilletantes who were not expected to win. We chose to study the universe of congressional primaries for one main important reason: Over the years, congressional districts have become less competitive and safer for one party or another.¹ As a result, attention has shifted toward primaries as an important factor in the motivations of representatives and senators, who fear being “primaried.”² Even though in congressional primaries, as in the general election, very few challenges to incumbents succeed, the fear of being primaried leads incumbent representatives and senators to anticipate challenges and adapt to the possibility of being primaried. This is one important contributor to the political polarization that has become such a feature of modern American politics.³

Past qualitative research by Elaine Kamarck and James Wallner on incumbent members of Congress has found that incumbents:

• Worry about a primary threat.
• Believe contested primaries hurt their chances in the general election.
• Exaggerate the importance of successful primary challenges and;
• Believe that changes in their behavior can help defer or defeat primary challenges.⁴

A December 2024 qualitative study by J.D. Rackey and Michael Thorning interviewed members of Congress and reached similar conclusions. They found that “primary elections do play a major role in both the structure of the congressional floor agenda and individual member’s voting decisions.”⁵ They also found that primary elections affected member communications. “Members calibrate their message and tone to ward off or defend against primary challenges…”⁶

Thus, primary challenges—real or potential—affect member behavior. This is why the study of congressional primaries has become more and more important. This is the fifth study Brookings has conducted on the candidates who run for Congress in both parties. As in the previous studies (2014, 2016, 2018 and 2022), we designed a coding sheet and over the course of the 2024 primary season, a team of coders combed the websites, social media, and public interviews of all 2,048 people who made it onto their party’s 2024 primary ballot. We obtained information on demographics, issue positions, and overall political ideology. To maintain inter-coder reliability, we met twice a week to share findings and ensure consistency in how we characterized candidates

We will start by looking at the demographics of who runs for Congress. Then we’ll look at where they place themselves, if at all, within the factions that exist within their political party. Finally, we will examine the issues they run on. These fall into two groups: issues which many candidates ran on and those which were less frequently mentioned. On all issues, we will look at differences between parties and within parties. Tables that are not in the text can be found in the comprehensive appendix at the end of this paper. 

In general, we find several important results:

• Women represent only around a quarter of congressional candidates.
• About two-thirds of candidates are white.
• Congressional candidates are more highly educated than the general public.
• The two largest categories were MAGA Republicans and Mainstream Democrats.
• Most candidates focused on just a few issues, with Republicans focusing on immigration, guns, law and order, and taxes while Democrats emphasized abortion, climate change, and health care.
• Issues such as transgender rights and critical race theory attracted relatively little attention from the candidates.
• Open primaries where Independents could vote helped elect more moderate candidates, suggesting a way election reform could nibble away at political polarization.

Despite all the progress women have made in the political world, they still constitute a minority of congressional candidates. In 2024, women represented 25% of all congressional candidates, and men 75%. Overall, men won more races than women, largely because most incumbents are men, and incumbents win significantly more races than non-incumbents. In fact, when we look at female candidates running in races without incumbents, they do much better. Two hundred and ninety-five women ran in essentially open races, and 47% of them won their primaries.

In all the years we have studied congressional candidates, including 2024, more women ran as Democrats than as Republicans.

The field of candidates was also predominantly white. Sixty seven percent of candidates were white, 13% were Black, 8% were Hispanic, and 6% were Asian American and Pacific Islander (AAPI.) Unsurprisingly, twice as many Black candidates ran as Democrats than as Republicans. Hispanic and AAPI candidates, meanwhile, were more closely divided between the parties.

Congressional candidates were also much more highly educated than the general public. Only 7% had less than a four-year college degree, 29% held a bachelor’s degree compared to 23% of the general public, and 46% had a graduate degree compared to 14% of the general public.⁷ When broken down by party, Democrats had more candidates with graduate degrees than Republicans, and Republicans had more candidates with just bachelor’s degrees than Democrats.

Regarding occupation, 30% of candidates were business owners or executives, while 14% were lawyers. Among lawyers, Democrats outnumbered Republicans; among business owners, Republicans outnumbered Democrats.

On religion, 53% identified as Christian, 10% as something other than Christian, and 38% gave no indication of religious affiliation. Among the Christians, evangelical Christians were overwhelmingly Republican, an indication of how politicized the evangelical movement has become. Back in 1976 when Jimmy Carter ran for president, the evangelical vote united Black voters with northern Catholics and Jews to vote for Carter.⁸ But since then, more than 50% of evangelicals vote or lean Republican.⁹

Most of the candidates (55%) were married. Only 3% were openly gay, up from 1.6% in 2022.¹⁰ Twenty percent served in the military compared to 17% in 2022, and 4% were current or former members of labor unions. 

One of our primary objectives in this research was to uncover the factional divides within each political party. To that end, we coded the Republicans as MAGA (Make America Great Again) Conservative, Mainstream Conservative, or Moderate Republican. We coded the Democrats as Mainstream Democrat, Progressive, or Democratic Socialist. We based our codes on a combination of policy positions, rhetoric, and candidate self-identification, such as, “I am a proud America First conservative.” We relied on a few key indicator variables to code candidates on the edge between codes. For Democrats, analyzed the presence of progressive rallying cries on their website, like “Green New Deal” or “defund the police,” as well as positions on “Medicare for All” and positions questioning U.S. support of Israel. For Republicans, we looked at photos of Trump, mentions of Trump, and Trump-style rhetoric¹¹ (e.g., “MAGA,” “America First”) on websites; views on January 6 and the 2020 election; and positions on support for Ukraine. We also defaulted to candidates’ self-identification for this question. For example, if a Democratic candidate took generally moderate policy positions but described themselves as progressive, we coded them as a Progressive rather than a Mainstream Democrat.

As Table 1 indicates, most Republican candidates (46%) ran as MAGA candidates, a number consistent with the long running narrative that Donald Trump has had enormous influence on the modern Republican party. In just two years Trump increased his hold over the Republican party. In 2022, 36% of Republicans ran as MAGA candidates and 47% ran as Mainstream Republicans.¹² Nonetheless, there were still Mainstream Republicans and even a few Moderates running in 2024—indicating that the Trump takeover was not total.

On the Democratic side, Mainstream Democrats (in the Clinton, Obama, and Biden mold) outnumbered Progressive Democrats by two to one (60% to 30%.) Although Republicans frequently refer to Democrats as far-left, (Trump often called Harris a Marxist during the campaign) there is scant evidence of socialism in the Democratic party. Only six Democratic House candidates and one Senate candidate (Senator Bernie Sanders (I-VT)) refer to themselves or have referred to themselves as Democratic Socialists. Of the six House candidates, three won their elections and three lost.¹³

Which factions were more successful than others in winning their primaries? Figure 2 shows that on the Republican side most MAGA candidates won their primaries, but Mainstream Conservatives, although smaller in number than MAGA Conservatives, also won primaries. Moderate Republicans have been and continue to be a dying breed, as evidenced by their small numbers.

On the Democratic side, Mainstream Democrats outperformed Progressives, constituting 67% of primary winners. Democratic Socialists are even scarcer than Moderate Republicans, with barely 1% of the Democratic field identifying as such.

Another way to conceptualize ideology is to look at some of the flash points in modern American politics and examine their salience in congressional primaries. Take, for instance, the call to “defund the police” that rocketed to prominence in 2020 and turned out to be very unpopular with the broader electorate—so much so that the revered Democratic Congressman Jim Clyburn (D-SC) and many others blamed it for the loss of several congressional seats in 2020.¹⁴ By the 2024 primaries, the slogan had been widely discredited, even though calls for police reform had not been. Only 13 Democratic candidates—0.15% of candidates—used the phrase “defund the police” positively in their campaign materials.

Another flash point for Democrats appeared midway through the primary season as protests broke out on college campuses against Israel’s military actions in Gaza, creating a split within the Democratic Party that some predicted could turn Joe Biden’s 2024 Chicago convention into a modern version of Hubert Humphrey’s 1968 Chicago convention. But the divisions never got that deep. Only 69 Democratic candidates (or 8%) of all Democratic candidates mentioned genocide and/or total opposition to U.S. support for Israel. More called for a ceasefire or conditions on American aid to Israel (18%). But overall, 31% either supported Israel unconditionally or supported Israel along with calls for humanitarian aid for Gaza.

On the Republican side, the flash points tended to be around the legitimacy of the 2020 election. Only 45 Republican candidates (5%) of the total said that Biden won the election fairly. Fully 23% said that Biden’s win was a big lie or that the election should have been investigated further. However, most Republican candidates—723, or 72% of the total—stayed away from the topic altogether. Similarly, 839 Republicans or 82% of the Republican candidates refused to discuss the January 6th riot at the Capitol. These findings underscore the advice Republican political professionals were giving to Trump and other Republicans during the campaign—to stay away from the past.

• In sum, the picture that emerges from this look at the congressional candidates is as follows: While the Republican Party has been transformed by Trump, the transformation is not complete; there are still mainstream Republicans running for Congress. In a closely divided House of Representatives some more moderate members or members who fear being “primaried” by a moderate could join with Democrats to make a majority on key issues.
• Republican congressional candidates did not think running on complaints about the 2020 election made for good politics.
• The Democratic Party is not nearly as left wing as their critics like to make them out to be. Only eleven (ten House candidates and one Senate candidate) out of all Democratic candidates identified as Democratic Socialists and only half of the Democratic Socialists won their primary.
• Incendiary talk about defunding the police has practically disappeared and opposition to Israel’s military actions in Gaza was much smaller than anticipated.

Some years ago, political scientists Norm Ornstein and Tom Mann popularized the notion of “asymmetric polarization” and argued that it was worse among elites such as lawmakers on the Republican side than it was among lawmakers on the Democratic side.¹⁵ The ongoing work in The Primaries Project offers more systematic evidence that polarization is worse on the Republican side than on the Democratic side, and that moving far right is received more enthusiastically among Republican voters than moving far left is among Democratic voters.

Not every candidate had positions on all the issues of the day. Unsurprisingly, incumbents had the most extensive record on issues since they had to cast votes on many of them. But most other candidates concentrated on only a few issues with distinct differences between the parties and few differences within them.

The following graphic shows the top issues mentioned in the 2024 congressional primaries: Immigration, abortion, guns and the Second Amendment, climate change, police and criminal justice reform, and health care.

Immigration

As is evident, some issues—immigration, guns, police reform and taxes were discussed by more Republican candidates than Democratic candidates; while abortion, climate change, and health care were discussed by more Democrats than Republicans. This is consistent with our previous findings that Democrats and Republicans have two distinct conversations in their primaries.

The top issue for Republicans was immigration, with the overwhelming number of candidates saying that they would either close the border or otherwise secure it by, for instance, building a wall or arresting and deporting undocumented immigrants. Almost no Democratic candidates took this position, but instead overwhelmingly supported comprehensive immigration reform. For some years now Democrats have been accused of favoring open borders but only four Democratic candidates (out of 841) mentioned a position in favor of open borders, such as abolishing ICE, in their campaign materials.¹⁶ This is consistent with our findings that while Republican candidates often attributed far left positions to their Democrat opponents, there was little in the campaign materials of those Democrats to support the attacks.

Abortion

Abortion was the top issue for Democrats, with an 84% mention rate, though most did not go into detail on their position. The vast majority, 78%, simply said they were pro-choice without further elaboration, though most also stated they favored enshrining abortion rights on the federal level. Thirty seven percent of Republican candidates failed to mention abortion at all. Of those who did, most simply stated they were pro-life with no elaboration. Republicans were also hesitant to touch the issue of a national abortion ban, with just 7% expressing support for a ban and most refraining from mentioning it at all.

Obviously, the Supreme Court’s decision sending abortion rights back to the states made a huge difference in the relevance of this issue. In 2016, the last presidential election for which we have data on congressional candidates, Democrats largely stayed away from the issue.

Guns

Approximately two-thirds of the congressional candidates in each party expressed an opinion on gun control and not surprisingly they took opposing positions; with Democrats expressing support for stronger gun laws and Republicans expressing support for the Second Amendment and opposed to new gun laws.

Climate change

On climate change, 39% of Democrats expressed general concern for the environment and 36% identified climate change as an existential threat or urgent challenge. Republicans generally dealt with the climate issue by ignoring it—57% did not address it in their campaign materials and of those who did 25% acknowledged the existence of climate change but said that addressing it should not come at the cost of ruining the economy. This is consistent with our findings from earlier studies; Republican candidates tend to ignore the issue of climate change. Only 6% of Republican candidates were outright climate deniers compared to 15% of the general public that denies climate change.¹⁷

Taxes and regulation

On questions of taxation and regulation, virtually no Democrats advocated lowering taxes and getting rid of regulations and virtually no Republicans advocated making the rich pay their fair share.

Police and criminal justice reform

On questions of policing and criminal justice reform Republican candidates were almost unanimous in their support of law enforcement, with only 2% of their candidates advocating police reform. Democrats were much more inclined to support police reform, though only 2% of the Democratic candidates used the phrase “defund the police.”

Health care

Health care continued to be a big issue for Democrats who were split between those who wanted to expand, reform and protect the Affordable Care Act (44%) and those who advocated for Medicare for all or a single payer system (29%). However, those wanting to expand the Affordable Care Act were twice as successful at winning their primaries. Most Republicans did not mention health care, and among the few that did, most focused on controlling Medicare costs or calling for less government spending.

Unlike the off-year election of 2018 where health care was such a major issue that Speaker Nancy Pelosi credited it with winning back the House for the Democrats, health care did not play the major roll it did in the 2018 midterm elections.¹⁸ By 2024, the issue of the Affordable Care Act or Obamacare, had faded and only 7% of Republican candidates advocated for repeal of the Affordable Care Act.

Israel and Ukraine

On the two most important foreign policy issues of the day—the wars in Israel and Gaza and Ukraine candidates for the two parties took very different positions. As the following tables indicate, Republican congressional candidates were much more likely to offer unconditional support for Israel in its war in Gaza than were Democratic candidates. But on Ukraine the picture flips; Democrats are much more likely to offer unconditional support for Ukraine while nearly one-third of Republicans who mentioned the issue supported ending all aid to Ukraine.

There were a set of issues that were mentioned by fewer than 50% of the candidates. For instance, during the primaries there was a constant stream of commentary and reporting on the age of the two leading presidential candidates, Trump and Biden. But fewer than 11% of the candidates mentioned age of the presidential candidates and they were mostly Republicans attacking Biden. Very few candidates wanted to discuss the January 6th riots on Capitol Hill, or who won the 2020 presidential election and most of those who did were Democrats. And very few candidates wanted to discuss Trump’s legal problems—most of those were Republicans who wanted to blame the Democrats.

Very few candidates waded into the hot-button issues around the treatment of transgender people, but an equal number of Democrats and Republicans expressed an opinion—with Republicans critical of rights for transgender people and Democrats supportive. The same was true of critical race theory—although few candidates expressed an opinion, nearly all the Republicans who mentioned it were critical. Seventy eight percent of the Democrats stayed away from the issue entirely and instead made bland statements saying the government has a legitimate role in education.

On prescription drug prices, most Republicans (84%) said nothing and the Democratic candidates who did bring it up were almost universally supportive of government efforts to control the costs of prescription drugs.

Among the least mentioned issues were two surprises: COVID-19 and inflation. We almost decided not to code for COVID-19 related issues (opinions on mandatory vaccines and lockdowns) but decided it might still be relevant. While only 39% of all candidates expressed an opinion about mandatory COVID-19 vaccines, 40% of all Republican candidates expressed some degree of opposition to mandatory vaccines. They were clearly seeking support from that segment of the Republican electorate that continues to see mandatory vaccines as an intrusion into their freedom. This explains why Robert F. Kennedy Jr. was so warmly welcomed into the Trump camp. Virtually no Democrats expressed opposition to vaccines. The situation was similar when it came to candidates’ positions on mandatory lockdowns. Almost all the Republicans who took a position were strongly opposed to lockdowns and virtually no Democrats took this position.

Given how important inflation has been to the politics of 2024, it surfaced somewhat infrequently as a topic, with only 42% of congressional candidates mentioning it in their campaign materials. Of those who did, the vast majority were, not surprisingly, Republicans—only 19% were Democrats. All of the Republicans used inflation to attack the Democratic Congress and President Biden.

This look at America’s two political parties circa 2024 yields some important lessons. First and foremost, the two political parties represent clear and distinct policy differences. These differences extend from domestic issues like guns and abortion to foreign policy issues like Israel and Ukraine. When a “Democratic” issue is front and center in a given election year, like health care was in the 2018, Democrats do well. When a “Republican issue” like immigration is front and center as it was in 2024, Republicans do well. The salience of issues can vary from election to election. Given the importance of abortion in the 2022 and 2023 elections, many thought that it would help the Democrats in 2024 but by then state referenda had been successful in resorting or securing abortion rights in even the most Republican states and Trump had vowed to veto a federal abortion ban, so many pro-choice voters felt free to vote for Trump.

Second, the extremes within each political party are not equivalent—the MAGA right wing is a lot larger and more important to the Republican Party than the progressive left wing is to the Democratic Party. In both parties, mainstream candidates win slightly more of their races but in the Democratic Party mainstream candidates and mainstream winners are much more numerous than Progressives. Given the moderation of Democratic congressional candidates it remains a mystery why, come presidential election time, Democrats are so ill-prepared to counter Republican attempts to paint them as fundamentally out of sync with American values. From the Willie Horton ads that made such a difference in the 1988 campaign, to defund the police to sex change operations for prisoners, Democrats have a hard time expressing their tolerance in the mainstream of American values.

Finally, political reformers concerned about America’s extremely polarized political system have been searching for a structural reform that could decrease polarization. Some have argued that closed party primaries, where Independents cannot vote, exaggerate the strength of the more extreme elements of each party and thus polarize our politics. To test this, we looked at our winning candidates by type of primary as can be seen in the following table.

Although the relationship is not perfect, the table indicates some support for the view that nonpartisan primaries help elect more moderate congressional candidates in the Democratic Party at least. In closed primary states only registered members of a specific political party can vote in their primary. On the Republican side, MAGA and Mainstream Conservative candidates won about evenly in the 12 closed primary states. On the Democratic side progressives did much better than mainstream Democrats. The next two primary systems allow some voters other than registered party voters to participate in primaries. There are 18 states that fall into these categories, semi-closed and semi-open primaries, and the results show no particular pattern.

In the 16 states that allow all voters to choose which party they can vote in without registering for a party there appears to be no difference on the Republican side where MAGA and Mainstream candidates did as well as each other. However, on the Democratic side mainstream candidates clearly do better than Progressives.

And finally in the two nonpartisan primaries Mainstream Conservatives and Mainstream Democrats do better than more extreme candidates. However, since there are only three of these states so far—Alaska, Washington, and California—it remains to be seen if this result has more to do with unique features of the state than the form of primary; however, the results are promising. The largest states in this group, Washington and California, are Democratic states and it could be that even those voting in Republican primaries prefer more moderate congressional candidates.

Studying congressional candidates is one way to better understand the state of America’s two parties and on the polarization that has affected our politics. Our first conclusion is that the polarization has indeed been asymmetric, affecting the Republican Party more than the Democratic Party. This is often overlooked for two reasons. First, the Republican Party works hard to paint all Democrats as socialists who would wreck the economy, defund the police, open the borders, and lobby children to question their sexuality.¹⁹ The second is the inclination towards what the distinguished journalist Marvin Kalb had called “the journalistic curse called bothsideism.”²⁰

“Bothsideism” is the assumption that that if the Republican Party is being led to the far right, the Democrats must be being led to the far left. Our data shows that there’s not much evidence to support the far left tilt of Democrats.

Secondly, what little data we have suggests that opening up primaries to a larger slice of the public may, in fact, result in the election of more moderate congressional candidates. If that is, indeed, the case, incumbents in those states should feel somewhat liberated from the curse of being “primaried” and may open the door to a less polarized politics.

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