Trump and his backers are raking in campaign cash. But not all of it is to help Republicans. Some of it may be to defeat the ones who dare criticize him — even while voting for his agenda.

Much attention has been given to how successful Donald Trump’s fundraising efforts have been in the first year of his presidency.

A month ago, Trump held a massive fundraiser at his D.C. hotel that netted $10 million. And despite the fact that their president is lurching from scandal to scandal, Republicans generally have been outraising Democrats for the past few months.

But this may not entirely be good news for Republicans. Trump is not planning to use all of this money to help them. In fact, there are signs he is planning to use some of it against Senate Republicans who have drawn his ire.

Trump has never much liked the Senate Republican caucus. Outraged by their failure to repeal Obamacare, Trump is trying to threaten Senate Majority Leader Mitch McConnell’s job, and on Thursday, he took a break from his 17-day golf vacation to demand McConnell “get back to work.”

But there are specific senators he has special anger for, to the point that he and his allies are actually toying with the idea of spending money to defeat them.

Back when it looked as if Sen. Dean Heller (R-NV) might vote against Obamacare repeal, Trump openly threatened his job at a conference, saying “He wants to remain a senator, doesn’t he?”

And pro-Trump outside spending group America First Policies announced a seven-figure ad buy against Heller, warning “we’re not giving him a second chance” if he voted no on repeal. They canceled the campaign only after Heller had safely voted yes.

Sen. Jeff Flake (R-AZ) is facing similar threats. Robert Mercer, technology billionaire and Trump megadonor, is spending $300,000 to back Flake’s primary challenger, Kelli Ward. White House press secretary Sarah Huckabee Sanders recently refused to rule out the possibility Trump himself will follow suit, saying, “Sen. Flake would serve his constituents much better if he was less focused on writing a book and attacking the president.”

It is worth noting that neither Heller nor Flake has ever actually voted against Trump on any matter of political significance. While they have publicly criticized some of his beliefs and policies on occasion, they confirmed all his nominees and voted the way he told them to. The unpopular and vulnerable Heller even voted for Trump’s health care bill, despite overwhelming opposition from his constituents.

It makes no strategic sense for Trump to spend money and political capital trying to take down two Republicans crucial to his narrow Senate majority. He has no plan here — just sheer pettiness. It’s also counterproductive for Trump to attack the very Republicans whose support he needs if he has any hopes of passing any of his legislative agenda.

In another political climate, Trump’s fundraising might be cause for GOP optimism. But it is clear that Trump is out for only himself — and is not above using his war chest to stab his Republican compatriots in the back.