Senate GOP Leader Mitch McConnell bluntly warned Republican senators in a private meeting not to sign on to a bill from Sen. Josh Hawley aimed at limiting corporate money bankrolling high-powered outside groups, telling them that many of them won their seats thanks to the powerful super PAC the Kentucky Republican has long controlled.

According to multiple sources familiar with the Tuesday lunch meeting, McConnell warned GOP senators that they could face “incoming” from the “center-right” if they signed onto Hawley’s bill. He also read off a list of senators who won their races amid heavy financial support from the Senate Leadership Fund, an outside group tied to the GOP leader that spends big on TV ads in battleground Senate races. On that list of senators: Hawley himself, according to sources familiar with the matter.

McConnell has long been a chief opponent of tighter campaign finance restrictions. But there’s also no love lost between McConnell and Hawley, who has long criticized the GOP leader and has repeatedly called for new leadership atop their conference. Just on Tuesday, Hawley told CNN that it was “mistake” for McConnell to be “standing with” Senate Majority Leader Chuck Schumer, a New York Democrat, in their push to tie Ukraine aid to an Israel funding package.