The unbreakable wall of Republican support that encouraged and enabled Donald Trump’s norm-shattering presidency cracked on Wednesday.

A group of 10 House Republicans joined Democrats to impeach Trump for inciting a deadly riot at the U.S. Capitol last week. Senate Majority Leader Mitch McConnell, R-Ky., hasn’t ruled out convicting Trump during a trial later this month, giving fellow Republicans cover if they chose that option.

The vast majority of House Republicans stood by Trump during the impeachment vote. But in a sign of the president’s weakening grip on the party, even some of those who opposed impeachment condemned Trump’s behavior and blamed him for sparking the insurrection.

“The president bears responsibility for Wednesday’s attack on Congress by mob rioters,” said House Republican Leader Kevin McCarthy, R-Calif., who has been a staunch Trump ally.

It’s a dramatic turn of events for a president who has enjoyed virtually unyielding loyalty from his party and was expected to play a key role in shaping the GOP’s future. But the impeachment vote demonstrated how challenging the coming months may be for Republicans.

While some are clearly eager to move into a post-Trump era, there’s still a large block that will stand with him even after he fueled a riot. Many House Republicans downplayed the significance of the insurrection and Trump’s role, drawing false comparisons between the deadly storming of the Capitol by a largely white mob and isolated incidents of looting and violence related to civil rights protests last summer.

“The left in America has incited far more violence than the right,” said Rep. Matt Gaetz, a Florida Republican who was among the 197 who opposed impeachment.

Still, the stunning nature of the mob violence shook many lawmakers. Rep. Liz Cheney, the No. 3 Republican in the House, gave rank-and-file conservatives the green light to abandon Trump in a scathing statement on the eve of the vote.

“There has never been a greater betrayal by a president of the United States of his office and his oath to the Constitution,” she said.

The president’s remaining allies warn Republicans who cross him publicly risk a conservative backlash in their next elections.

“Public and private polling shows Republican grassroots voters strongly oppose impeachment,” said Jason Miller, a Trump senior adviser. “Any Republican senator or congressman voting for impeachment will be held accountable in their next primary election.”