US intelligence agencies have been saying for a while that Russia interfered in the US presidential election, by helping Wikileaks obtain leaked emails from Hillary Clinton’s campaign and the Democratic party. But as various news outlets have reported, the CIA now believes Russia did this not merely to undermine the US electoral system, but with the deliberate aim of helping Donald Trump win.

Trump himself has been busy trashing this idea. Yesterday he dismissed the CIA assessment as “ridiculous.” Previously, a statement from his team called the CIA “the same people that said Saddam Hussein had weapons of mass destruction.” (The CIA report on Iraq’s weapons was actually inconclusive; it was the George W. Bush White House that claimed it contained “bulletproof” evidence.) Further discrediting the intelligence agencies, Trump also said yesterday that he didn’t read the intelligence update customarily delivered to the president each morning, but would “get it when I need it.”

But Trump’s obstinacy on this issue seems to be reopening, or at least exposing, rifts within the Republican party, which has up to now largely stood by its president-elect despite the insults and lies Trump aimed at senior Republicans during the campaign. Republicans are reacting to Trump’s dismissal of the Russian hacking claim in four main ways.

Calls for an immediate investigation

Republican senators John McCain and Lindsey Graham joined their Democrat colleagues Charles Schumer and Jack Reed in calling for an immediate, bi-partisan investigation. (McCain heads the Senate’s armed services committee; Reed is the ranking Democratic member of that committee; and Schumer is the leader-elect of the Senate Democrats.) In a statement on Sunday, the senators said “recent reports of Russian interference in our election should alarm every American,” and called on Congress to inform the public about the cyberattacks that have “cut to the heart of our free society” and “examine these recent incidents thoroughly.”

Facts “are stubborn things,” McCain told CBS on Sunday. “They did hack into this campaign,” he said, while repeating his assessment that Russian president Vladimir Putin was a “thug and a murderer and a killer and a KGB agent.”

Republican senators Rand Paul and James Lankford also both independently called for an investigation. And former Congressman Joe Walsh, who once threatened to take up arms if Trump lost, was an unexpected critic, calling for an immediate inquiry and berating Republicans who did not.

Taking aim at Tillerson instead

Rather than comment on what was potentially the biggest news of his entire political career—the reported interference in a US election by a foreign force—senator and former presidential hopeful Marco Rubio decided over the weekend to target Trump’s pick for Secretary of State, Exxon Mobil executive Rex Tillerson, for his close ties to Putin instead.

Tillerson’s nomination could be threatened by the Foreign Relations Committee, which includes Rubio.

Express concern, but do nothing

Speaker of the House Paul Ryan said through a spokeswoman that foreign interference in US elections is “unacceptable,” but stopped short of suggesting Congress do anything about it, adding that “he rejects any politicization of intelligence matters.”

Ryan said on Dec. 9—before the report about Russian interference came out—that he had had a “very exciting meeting” with Trump, which was reportedly about dismantling the US government-backed healthcare system. This is the same Ryan, remember, who slammed Trump in July for making racist comments about a judge and two months ago split with him publicly for his comments about sexually assaulting women.

Shrug, blame Hillary

One Republican acknowledged the report of Russian intervention, but suggested it didn’t matter.

Reince Priebus, Trump’s new chief of staff, said that Trump “trusts the CIA” (despite the Trump team’s earlier statement attacking the agency), and denied (falsely) that a previous intelligence assessment had named Russia as being responsible. In any case, he also said, Clinton lost the election not because of Russian hacking but because she didn’t campaign enough in key battleground states.