Few people expected John Kasich to make it this far. The Ohio governor has improbably outlasted a long list of Republican rivals in his effort to win his party’s presidential nomination—and continues to run a long-shot campaign. It is now mathematically impossible for Kasich to secure the Republican nomination. Still, Kasich refuses to quit, hoping to prevail at the Republican convention in July with the argument that he’s the best candidate to unite the party and defeat Hillary Clinton.

As he hangs on, the governor is making at least some conservatives who want to see Donald Trump defeated uneasy. “I think it does hurt [Ted] Cruz’s ability to rally people against Donald Trump,” Erick Erickson, editor of the conservative website The Resurgent and a prominent anti-Trump voice on the right, lamented, commenting on Kasich’s decision to stick it out. “It’s very frustrating, but even more so because I get the sense that Kasich doesn’t care. John Kasich, I think, would be perfectly happy being a vice president to either Ted Cruz or to Donald Trump. He just clearly doesn’t care about stopping Trump the way most of the party does.”

Conservatives who fear Kasich could deal a blow to the effort to topple Trump have legitimate concerns. The Ohio governor could split the anti-Trump vote, and make it more difficult for the Republican Party to coalesce around Cruz, who has won far more delegates than Kasich, as the most viable alternative to the GOP presidential front-runner. “The evidence that we have right now is that Kasich is more hindrance than help to the Stop Trump movement,” said Josh Putnam, a political-science lecturer at the University of Georgia who closely tracks the delegate-selection process. “If we continue on the same trajectory that we’re on now with three candidates, that’s a situation where Trump is going to continue to win and get the bulk of the delegates and inch toward the nomination.”

Unsurprisingly, Team Kasich doesn’t agree. The campaign’s chief strategist John Weaver argued in a memo on Tuesday that “Kasich is the key to our Party’s hope of stopping Donald Trump and the potential disastrous consequences of his nomination.” The campaign points to the fact that Kasich is expected to outperform Cruz in Northeastern states as evidence that if he were to drop out it would create an advantage for Trump. Kasich has also ruled out the possibility of serving as vice president for either of the remaining GOP candidates in the race. “I’m running for president,” Kasich said indignantly in a recent interview on NBC’s “Meet the Press,” after being asked if he would act as either Trump or Cruz’s running mate.

Some Republican strategists agree that Kasich’s presence in the race could help slow Trump’s momentum in the Northeast. If the Kasich and Cruz campaigns worked strategically to deny Trump delegates that could also help the anti-Trump movement. For now, however, it’s difficult to envision that kind of coordination taking place. “Asking politicians to put their ego aside for the good of the party is a lot like asking a thief not to steal,” said Ford O’Connell, a Republican strategist who worked on John McCain’s presidential campaign.

The arguments and hand-wringing that have erupted over Kasich’s decision to stay in the race are emblematic of the broader disarray the Republican Party faces as it moves closer to the general election. Competing theories and disagreement over whether Kasich will hurt or help the anti-Trump movement highlight the difficulty of strategizing any definitive way to topple the GOP front-runner.

In the meantime, pressure is mounting for Kasich to exit the race. “I think at this point Kasich does need to get out,” Erickson said. “Kasich continues to weigh down the Cruz campaign and continues to prevent people from completely consolidating against Donald Trump.” Not everyone who wants to see Trump defeated is calling for Kasich to quit, though. “Nobody from our group would be advocating directly for Kasich to get out,” said Katie Packer, the founder of the anti-Trump super PAC Our Principles PAC. “If delegates and voters determine later that they [the Kasich campaign] were the reason that Trump hit 1,237 [the number of delegates needed to secure the nomination] then that is something they have to deal with,” Packer said, “But I don’t begrudge them keeping their eye on the target, and working hard toward that.”

For his part, Cruz has taken up the argument that Kasich is making it harder to stop Trump. “Right now Kasich’s role is really being a spoiler. Kasich benefits Donald Trump," Cruz told CNN earlier this week. “What Kasich can do is pull enough votes away to let Trump win.” Trump, meanwhile, also wants fewer candidates in the race. “While I believe I will clinch before Cleveland and get more than 1237 delegates, it is unfair in that there have been so many in the race!,” he tweeted on Wednesday.

It’s difficult to say exactly what would happen in a two-person matchup between Cruz and Trump since it is hard to predict which candidate Kasich’s supporters would gravitate to. A two-person race might allow the anti-Trump vote to consolidate and overtake Trump, or Kasich supporters might defect to Trump in large numbers. In the meantime, if anti-Trump Republicans can’t agree on how to respond to Kasich’s decision to stay in the race, it will be more difficult for the Never Trump movement to mount an effective campaign. If nothing else, Kasich could be a convenient target in the inevitable scramble to assign blame if the anti-Trump forces ultimately fail to take their adversary down.