“While the administration refuses to act against Turkey, I expect strong bipartisan support," Graham said. “Most members of Congress believe it would be wrong to abandon the Kurds, who have been strong allies against ISIS.”

Cheney's words were equally strong. She said “President Trump’s decision to withdraw U.S. forces from northern Syria is having sickening and predictable consequences” and vowed that lawmakers “must and will act to limit the catastrophic impact of this decision.”

Lawmakers in both parties have shown significant support for a continued U.S. presence in Syria this year. But whether Congress will able to do much about it is an open question.

Sen. Marsha Blackburn (R-Tenn.) was one of many lawmakers calling for sanctions on Turkey, for example, if the country continues invading Syria. But Republican leaders are hesitant to predict quick action, instead hoping they can rally the president to change his mind in the public sphere.

That's because, as Sen. Roy Blunt (R-Mo.) put it, Trump's actions are "pretty hard to undo" through Congress.

“The Kurds have been a great partner. ... Turkey under Erdogan has not been. I’m concerned about what can happen next,” Blunt said in an interview. “A lot can happen in a hurry and we’ll just have to see what happens when we get back. I wish the president would reconsider.”

Trump did not indicate he was having any second thoughts late Wednesday, however, telling reporters: "We are getting out of the endless wars. We have to do it." He also responded to criticism by chiding the Kurds, telling reporters that "they didn't help us in the Second World War, they didn't help us with Normandy, as an example."

The response from Republicans has been one of the most vocal challenges to Trump in his nearly three years in office. Some like Graham and Cheney called out the president by name, and others cast his decision-making in stark and dire terms.

The Kurds “actually fought on the ground. They had people dying. To just abandon them like that so the Turks can come in and slaughter them is not just immoral, it taints our reputation all over the world,” Sen. Marco Rubio (R-Fla.) said Tuesday. “It’s a terrible mistake. We’ll have to think of what options there are. I’m sure the Senate will, potentially, take some vote to disagree with that decision.”

“President Trump's decision to abandon the Kurds, our major ally in the fight against ISIS, was terribly unwise. Today, we are seeing the consequences of that terrible decision,” Sen. Susan Collins (R-Maine) said.

Trump has defended his actions as a much-needed withdrawal from the Middle East. But he was conducting some measure of damage control on Wednesday, releasing a statement about Turkey’s invasion of Syria: “The United States does not endorse this attack and has made it clear to Turkey that this operation is a bad idea.” He said Turkey is "committed to protecting civilians, protecting religious minorities, including Christians, and ensuring no humanitarian crisis takes place—and we will hold them to this commitment."

Despite the cascade of criticism from both Democrats and Republicans, Trump has gained plaudits from libertarian-leaning allies, such as Sen. Rand Paul and Rep. Thomas Massie, both Republicans from Kentucky. Paul tweeted that Trump is “the first President in my lifetime to understand what is our national interest and what is not. He is stopping the endless wars and we will be stronger as a result. The Cheney/Graham Neocon War Caucus has cost us too much fighting endless wars."

Trump called U.S. intervention in the Middle East the “worst decision ever made in the history of our country” and retweeted Sergio Gor, a Rand Paul aide, who asked why Democrats weren’t supporting Trump’s decision.

Historically, Democrats have been far more in line with dovish foreign policy and scaling back the U.S. presence in the Middle East. But liberals and more centrist Democrats alike have lashed out at Trump this week, with Sen. Tim Kaine (D-Va.) declaring that Trump has “left our allies at risk of being slaughtered and spurred massive additional instability.”

On MSNBC, Rep. Ro Khanna (D-Calif.) laid out why Trump is facing bipartisan criticism rather than more predictable opposition from GOP hawks.

“There are many Democrats that are for a responsible withdrawal from Syria,” Khanna said, arguing Trump moved without forging any sort of assurances for the Kurdish people. “What we should have done is get Erdogan to commit not to invade the Kurds. And we have extraordinary leverage. They are a NATO ally, we can say: ‘You won’t be part of NATO if you do this.’ We sell them weapons, we provide them economic aid.”

Khanna said “everything is on the table” if Turkey continues military actions in northeastern Syria. Both Senate Majority Leader Mitch McConnell (R-Ky.) and Speaker Nancy Pelosi (D-Calif.) have been critical of the president’s withdrawal from Syria. Congress could in theory insert language responding to the situation in Syria in either an upcoming spending bill or a defense policy bill, both of which are must-pass bills. A standalone bill like Van Hollen and Graham's would amount to all-out congressional pushback against Trump, something Republicans have been reluctant to pursue at this point.

Senate Minority Leader Chuck Schumer (D-N.Y.) said in Albany, N.Y., on Tuesday night that he expects “Congress will take some form of action.” A nonbinding amendment expressing support for a presence in Syria easily passed the Senate earlier this year with 70 votes, signaling there could be enough support to override a presidential veto.