The fight over the future of the Republican Party and former president Donald Trump’s role in it won’t have to wait for another potential presidential campaign in 2024. The 2022 election is shaping up to be a massive referendum.

The surprise retirement announcement by Sen. Roy Blunt (R-Mo.) on Monday means there are now five GOP senators calling it quits ahead of the 2022 midterms. That’s fully one-fourth of all members up for reelection, and that number could soon grow.

And as The Washington Post’s Paul Kane has written, these retirees come overwhelmingly from the “governing wing” of the party. While Republicans voted with Trump on most everything, there were gradations within the party. And the class of retirees is disproportionately weighted toward those more focused on legislation than provocation and culture wars. These are appropriators and establishment GOP figures. And they’re heading for the exits.

What’s more, their replacements could give the GOP caucus in the Senate a much different feel — if the party opts to go in that direction.

In Ohio, former state treasurer Josh Mandel (R) has made his support for Trump a centerpiece of his campaign to replace Sen. Rob Portman (R), who is retiring — even saying during his launch that the election was stolen from Trump — while a former state party chairwoman jumped in the race by pitching herself as a “conservative disrupter” fighting for Trump’s agenda.

In Pennsylvania, Trump supporters have made the race there a focal point, given Sen. Patrick J. Toomey (R), also retiring, voted to convict Trump in his impeachment trial. (Toomey narrowly avoided censure for that vote last week.)

In North Carolina, we could see a Trump on the ballot, with the former president’s daughter-in-law Lara Trump considering a run.

Alabama seems highly likely to elect a Trump loyalist to replace Sen. Richard C. Shelby (R), given the makeup of the state’s GOP and what happened in the 2020 race, in which Republican voters chose Tommy Tuberville over former senator and U.S. attorney general Jeff Sessions, who had run afoul of Trump in the latter role.

And Missouri presents yet another major opportunity for the Trump wing. The state already has Sen. Josh Hawley (R) — who spearheaded the effort to overturn the electoral-college results in Congress — as one of its senators. And just last week, former governor Eric Greitens (R) floated a Trump-y primary challenge to Blunt.

There’s a long list of Republicans in Missouri who could jump in the primary, too, including Secretary of State Jay Ashcroft, Treasurer Scott Fitzpatrick, Attorney General Eric Schmitt and Lt. Gov. Mike Kehoe.

But Greitens’s potential candidacy would be a particularly big test of where the party is. While many Republicans glommed on to Trumpism as it became ascendant in the party, Greitens was more in step with Trump at the outset than many of his colleagues. The St. Louis Post-Dispatch’s Chuck Raasch wrote about the many parallels in 2016, when Greitens was elected governor the same year Trump won the presidency.

The test goes deeper than that, though, for this reason: Less than two years into his term, Greitens resigned amid multiple scandals, including one involving allegedly unwanted sexual contact with his hairdresser and another involving allegations that he improperly used a charity donor list. Greitens was charged with two felony counts related to the latter and faced potential impeachment by the state’s GOP-controlled legislature when he resigned. The charges were later dropped.

Despite resigning, Greitens alleged the efforts against him amounted to the kind of “witch hunt” Trump faced during the Russia investigation. Lending credence to those claims was the indictment of an FBI agent who was indicted himself for his handling of the case.

Were Greitens to seek to reclaim his political career — as he has long suggested he might and as his efforts in conservative media suggest — it’s easy to see how he would deal with questions about the past allegations against him: by casting them as the deep state and even the party establishment trying to take him down.

Greitens and Mandel have gone further than almost any senator when it comes to Trump’s 2020 election challenge. While Hawley tried to overturn election results, he did so by citing states allegedly not following their laws and not focusing on Trump’s claims of widespread fraud. Mandel and Greitens, by contrast, have both pushed the baseless claim that the election was actually stolen from Trump.

Greitens in December pushed bogus claims by a Trump adviser that it was “impossible” that Joe Biden actually won. He has also pointed to debunked claims about dead people voting and ballot-stuffing. And when people acting on these beliefs stormed the Capitol, Greitens promoted the baseless idea that the Jan. 6 riot was the work of non-Trump supporters or provocateurs — something FBI Director Christopher A. Wray now says there is no evidence of.

Were he to be able to win a primary, despite much of the GOP establishment turning against him in 2018, that would be a statement about where the party is these days and where its base intends to take it. And that’s a statement recent elections suggest the base is only so happy to send, if for no other reason than to deliver a middle finger to politics as usual.

The states that now have open seats in 2020 are also disproportionately ones that trended toward Trump in the last couple of elections. Pennsylvania had gone blue in every election since 1988 before Trump won it in 2016. Ohio was one of the most important swing states before landing solidly on Trump’s side in both of his races. And Missouri was something of a swing state before Trump carried it by double digits twice.

The idea that Missouri, which Barack Obama only narrowly lost in 2008, could soon have Hawley and Greitens as its senators would just about say it all — particularly if Greitens is joined in the Senate by the likes of Mandel and Lara Trump.