Republicans are on track to spend significantly more than Democrats on their primaries in House races around the country, as GOP candidates move to show their loyalty to the former president.

So far, Republicans have spent about $55.5 million in their House primaries in 2024 compared to $26.3 million for Democrats, according to a new report by a political spending watchdog, AdImpact.

The spending on House races has been spread largely across eight states, Alabama, Arkansas, California, North Carolina, Texas, Mississippi, Illinois, and Ohio, with California, North Carolina, and Alabama attracting the main share of the spending.

Yet in spending already slated for the upcoming primaries in the remaining 42 states, Democrats are set to outspend Republicans $28.4 million to $17.1 million.

The high level of primary spending on the GOP side reflects the ongoing push by Republicans aligned with President Trump to oust some Trump-skeptical Republicans from office.

In another wrinkle for Republicans, the top fundraiser of any of their House candidates is a former speaker, Representative Kevin McCarthy, who has raised more than $15 million for the 2024 election even though he has chosen not to seek re-election.

Instead, Mr. McCarthy has launched a behind-the-scenes push to recruit primary candidates to run against former colleagues he sees as most responsible for his ouster, like Congresswoman Nancy Mace or Congressman Bob Good.

One of Mr. McCarthy’s top allies, Brian Walsh, said of the eight Republicans who voted to oust Mr. McCarthy: “There must be consequences for that decision.”

“These traitors chose to side with Nancy Pelosi, AOC and over 200 Democrats to undermine the institution, their fellow Republicans and a duly elected Speaker,” Mr. Walsh said in a statement

According to Politico, the effort to exact revenge cropped up in the wake of Mr. McCarthy’s ouster among donors, consultants, and other supporters of the former speaker.

The push for party purity has taken other forms, as well. In one state, Texas, the Trump-aligned attorney general, Ken Paxton, is personally campaigning against Republicans in the state legislature who voted to impeach him.

A political scientist at John Jay College, Brian Arbour, tells the Sun that he wouldn’t necessarily call the GOP primary process that is under way a “purge,” but says there does appear to be two main issues splitting Republicans in House races.

The first is a question of personality and the level of candidates’ loyalty to the former president. A good example of this in a high-profile race is in the Senate primary in Ohio, where Mr. Trump endorsed businessman Bernie Moreno over an Ohio state senator, Matt Dolan, even though Mr. Moreno was widely seen as a riskier candidate and there was little ideological space between the two.

“Did Trump endorse Moreno because of his ideological division that was different than Matt Dolan or because he was more likely to support Trump?” Mr. Arbour asks.

The other axis dividing Republicans in primaries is ideological, he says, and a good example of this is in the 2022 Ohio Senate primary.

In 2022 Mr. Trump endorsed Senator Vance over Ohio’s treasurer, Josh Mandel, and Mr. Dolan. While Mr. Vance positioned himself as the most loyal to Mr. Trump, he also stood as a nationalist in opposition to the neoconservative ideology that had dominated the GOP for decades. With six-year terms, the ideological battle has been slower to play out in the Senate.

The intra-party battles on the Republican side stand in contrast to the Democrats, a party that Mr. Arbour says has become chiefly defined by opposition to the Republicans.

“Democrats are shifting as a result not of choices they’re making but in response to Republicans,” Mr. Arbour says. “In general Democrats are the more disciplined party.”

A good example of Democratic discipline is in Michigan, where the party apparatus aligned behind Congresswoman Elissa Slotkin in the state’s Senate primary, despite multiple candidates expressing interest.