Trump runs into Republicans who won't bend

President Trump is making life hell for Senate Republicans, and they're returning the favor.

"I make no apologies for standing up to the president," Sen. Bill Cassidy (R-La.) told reporters after he got into a shouting match with Trump on Wednesday at a Senate GOP lunch. "I made it clear that I wasn't going to be bullied."

Why it matters: Trump's push for a pre-midterm elections crackdown, via the SAVE Act, has opened of the deepest GOP ruptures of his second term.

To his fury, Trump is finding that senators he's written off, alienated or even helped defeat in primaries are choosing Senate traditions over his political demands.

In the middle is Senate Majority Leader John Thune (R-S.D.), who's been blunt with the reality that Trump doesn't have the votes to get what he wants.

"I'm certainly not giving my consent to that," Sen. Lisa Murkowski (R-Alaska) told reporters Wednesday about ending the filibuster.

Zoom in: Trump's lunch with Senate Republicans only seemed to move White House-Senate relations from bad to worse.

It became a shouting match with Cassidy over the administration's lack of information-sharing with the Senate on Iran.

Trump rubbed Cassidy's primary defeat last month in his face during the closed-door meeting, sources told Axios.

Just before the lunch, Trump canceled an event to sign and tout a bipartisan housing package, a bill the White House praised Tuesday as "one of the most significant pieces of housing affordability legislation in American history."

Trump said he would not sign the bill until the SAVE Act, requiring voter ID and proof of citizenship to vote, is passed.

Last week, Trump delayed the Senate confirmation process for Jay Clayton, ensuring Bill Pulte would serve as acting director of national intelligence, at least temporarily.

The president has continued his long campaign against the filibuster, which requires 60 votes to pass most legislation in the Senate, and the blue slips process, which allows senators to block judicial nominations in their state.

👎 The other side: The bloc of GOP senators willing to defy Trump has grown.

Cassidy and Sen. John Cornyn (R-Texas) have been far more willing to speak their mind since losing recent primaries to Trump-backed candidates.

They join Sens. Mitch McConnell (R-Ky.) and Thom Tillis (R-N.C.), who are leaving the Senate and have less reason to fear Trump's political blowback.

That's on top of the usual suspects like Sens. Susan Collins (R-Maine) and Murkowski, who have long been willing to vote against their party.

The bottom line: It's a midterm year. Republicans want to talk about affordability and hammer democratic socialists.

Instead, they're sitting through presidential rants about the filibuster and legislation with no clear path through the Senate.