A head-spinning few days in the presidency of Donald Trump are spiraling into a defining moment for the political movement he has led – and are raising questions about where the Republican Party goes from here.

This week’s equivocations and contradictions by the president, while fitting a pattern that’s played out before, have come on a matter of both utmost interest and import.

Whether or not his lack of clarity is intentional, Trump is forcing GOP members of Congress to choose sides on a wrenchingly uncomfortable topic. It’s playing out barely 100 days from an election that, according to US intelligence agencies, the Russian government is again trying to interfere with.

Do Republicans continue to line up behind a president who continues to contradict both himself and U.S. intelligence agencies? Or do they take stands on questions of national security and election integrity?

“The dam has broken,” Senate Foreign Relations Chairman Bob Corker, R-Tenn., who has emerged as a frequent Trump critic, told reporters on Tuesday. “What we’ve got to figure out is how do we deal with it.”

Corker’s judgment came before Trump seemed to say on Wednesday, in response to a question from ABC’s Cecilia Vega, that Russia is no longer targeting the United States. That again would undercut the assessment of his administration’s own intelligence officials, including Director of National Intelligence Dan Coats.

The White House said hours later that Trump wasn’t actually answering the question he was asked, and was saying “no” to answering questions at all.

That explanation came a day after Trump himself clarified his statement from Monday when he stood next to Russian President Vladimir Putin and seemed to back Putin’s assessment that Russia did not meddle in the 2016 election. Trump said he actually meant to say the opposite of what he had said.

Lost yet? That’s how a growing number of Republican lawmakers feel, as they find themselves defending presidential statements they are having a hard time understanding.

“I’m selling peace and prosperity, and if I don’t have prosperity or peace, we’ve got a problem,” one Republican member of Congress told a group of reporters Wednesday, speaking on condition of anonymity to frankly discuss political strategy. “So the last week, we’ve got a problem.”

Even aside from this week’s Russia detour, Trump took his party in unexpected directions by questioning the value of NATO, insulting his host government in Great Britain, and continuing his crusade against Robert Mueller’s special counsel probe.

The member of Congress said it’s unlikely that many votes will be cast on the issue of Russia alone. But as part of the broader climate of uncertainty, with alliances being tested, a trade war threatening the economy, and Democrats motivated by issues like the separation of families at the border, Republicans are sensing political threats.

Democrats see an opportunity for a newly powerful issue, one that might grow depending on events.

“The president has made a clear case that he is not to be trusted when it comes to the interest of the American people,” said House Democratic Leader Nancy Pelosi.

This moment, of course, could fade. It’s happened before: Trump says something impolitic or outrageous, takes a half-step of a walk-back, and then lands about where he started – usually louder than ever. The news cycle moves on.

Trump has almost always been able to count on his allies and the Republican Party he dominates to go along for even the wildest of rides. On Wednesday, White House Press Secretary Sarah Sanders pointed to “massive media hysteria,” and chided reporters to “quit going after the Trump administration for every little thing.”

This could be a big thing, though. Trump tweeted Wednesday that fallout from Monday’s appearance with Putin was impacted by “Trump Derangement Syndrome,” suggesting that his critics were going too far in offering critiques.

But the stance of Trump’s allies, rather than his enemies, is being tested at this moment.