In the wake of Donald Trump’s primary victories, Republican leaders felt they had no choice. They meekly fell in line and endorsed Trump. Even people like House Speaker Paul Ryan — who had the strongest moral qualms about backing a man who was not only unfit for the presidency but also promoting positions at odds with the core conservative values of the GOP — eventually backed him. At their convention in Cleveland they dutifully nominated him and did their best to suppress dissent. Moreover, just as was the case when Trump deemed a judge of Mexican heritage incapable of rendering fair judgment, Republican leaders refused to walk back their endorsements when Trump made egregious disparaging remarks about the Muslim parents of a slain American solider this past weekend.

But how has Trump responded to the servile partisanship that has caused them to stick with him? With nothing but contempt for them.

In an interview with the Washington Post on Tuesday Trump made it clear once again that he is not interested in making a long-anticipated pivot to presidential behavior or more disciplined messaging. But he’s also demonstrating that he has no interest in working with or conciliating Republicans who are uncomfortable with his vile behavior.

When asked if he was supporting House Speaker Paul Ryan for re-election against a primary challenger next week, Trump mimicked the speaker’s initial reluctance to endorse him saying, “I’m just not there yet.” Trump thanked Ryan’s primary opponent Paul Neheln for supporting him in his attacks on the Khan family this week after Ryan distanced himself with his belittling of the Khan family. Trump praised Nehlen for running a good campaign and then seemed to disparage Ryan by seeing “we need strong leadership,” when asked about why he hadn’t made up his mind about supporting him. For good measure, Trump also said he wasn’t endorsing John McCain for re-election to the Senate in Arizona and also singled out Senator Kelly Ayotte of New Hampshire for criticism for not backing him ardently.

For Trump, no grudge is too small and no resentment too insignificant to cause him to refrain from venting his spite against all those who are not sycophants. Considering that all three had swallowed hard and endorsed Trump his refusal to repay the favor speaks volumes about the man Republicans have chosen to head their party.

What possible motive is there for Trump to be picking fights with fellow Republicans who have endorsed him in the middle of a life and death struggle with Hillary Clinton that he is currently losing?

The only answer is the same one that would explain his rants about Judge Gonzalo Curiel or the Khan family. He not only can’t help himself. It’s clear that, much like his attitude toward foreign policy, Trump isn’t interested in allies. He wants only followers. Independent minds must be forced into abject submission. If that means damaging the man upon whom he will have to depend for legislation or undermining GOP senators in competitive races that Republicans must win in order for him to govern if he wins, so what? That means nothing to Trump.

That this is incredibly immature and political insanity of the first order almost goes without saying. But it also shows that the rational if unprincipled political calculation that was the basis for the decision of Ryan and the rest of the Republican leadership to acquiesce to Trump’s takeover of their party was profoundly mistaken.

In defending his decision to back Trump Ryan said that he believed Trump and a Republican Congress could together achieve the reforms he believes the country needs. But the problem with Trump isn’t just that he can’t trolling perceived foes or stop saying foolish things that distract voters from the failures of the Obama administration as well as Hillary Clinton’s lying and atrocious record. It’s that he will never cooperate with Congressional conservatives. The only agenda of a Trump administration will be what flows from his mouth and those who do not applaud the new GOP duce will be treated as enemies not friends who need to be wooed and conciliated. If he wins, GOP leaders will have helped enable a figure that they will not only be unable to control or even work with. They will have empowered someone who won’t hesitate to use the full power of the presidency to crush them and all they stand for.

Trump has given Republicans ample proof that if elected there will be no effective check on his worst authoritarian impulses. In effect, Trump is double daring Ryan, McCain, Ayotte and any other Republican with a conscience to do as President Obama bid them yesterday and rescind their endorsements. He knows they are too scared of being branded as traitors to their party — the way Ted Cruz has been lambasted for having the temerity to stand up to the mob of Trump supporters at the Cleveland convention — to take that dare. They also don’t want to be blamed for Trump’s likely defeat in November. But their mistake is not just that they faltered when it was still possible to take action to stop Trump. By standing with Trump even when he demonstrates his unfitness for the presidency they have unleashed a political tyrant who won’t rest until all his GOP opponents are crushed by him or dragged down to defeat in his wake. If they go any further down the garden path with him, they will have no one but themselves to blame when the voters make them pay for it in November.