President Trump faced a swift torrent of Republican criticism Monday as lawmakers rebuked his plan to withdraw troops from northeast Syria, a move Senate Majority Leader Mitch McConnell said would undermine U.S. national security and potentially bolster Islamic State terrorists.

McConnell (R-Ky.), in a rare public split with Trump, said that a supermajority in the Senate disagreed with the president’s abrupt withdrawal announcement, raising the specter of veto-proof action to oppose the decision.

“A precipitous withdrawal of U.S. forces from Syria would only benefit Russia, Iran, and the Assad regime,” McConnell said in a statement Monday. “And it would increase the risk that ISIS and other terrorist groups regroup.”

McConnell’s statement, in which he called on Trump to “exercise American leadership” and reconsider his plan to withdraw troops from Syria’s border with Turkey, echoed the comments of other Republicans who condemned the president’s decision Monday. The mounting opposition means that Trump is facing some of the sharpest criticism he has received from his party at the same time that his political survival could be in the hands of Republican senators forming a bulwark against a growing impeachment threat.

Several senators said Monday that Trump's move would undermine U.S. credibility, because it would mean abandoning U.S.-allied Kurdish fighters ahead of a long-threatened Turkish offensive into northern Syria.

"This betrayal of the Kurds will also severely harm our credibility as an ally the world over," Sen. Patrick J. Toomey (R-Pa.) said in a statement. "President Trump should rethink this decision immediately."

Responding to the Republican criticism Monday, Trump said that he had "consulted with everybody" but held back from his usual tactic of attacking any critics, saying that he respectfully disagreed with those opposed to his decision.

"I could name other people who are thrilled," he told reporters.

While Democrats roundly criticized the troop withdrawal, the outpouring of opposition from the president’s party stood out.

Trump, who is facing an impeachment inquiry over his push to get foreign governments to investigate political rivals, is relying on support from Republican senators to remain in office. Trump has publicly lamented the lack of unity among Republicans during the impeachment process.

Most Republicans have been reluctant to criticize Trump’s calls for Ukraine and China to investigate former vice president Joe Biden, a political opponent, and his son Hunter — acts that have become central to Democrats’ impeachment investigation.

But Trump’s move to draw down troops in Syria, announced Sunday night in a White House statement, opened him up to direct criticism from some of the lawmakers who have tried to defend him in the impeachment inquiry.

Sen. Lindsey O. Graham (R-S.C.), who has called impeachment attempts “ridiculous,” blasted Trump’s Syria decision Monday.

“So sad. So dangerous,” he said on Twitter. “President Trump may be tired of fighting radical Islam. They are NOT tired of fighting us.”

Sen. Marco Rubio (R-Fla.), who defended Trump by saying the president was not being serious when he called on China to investigate Biden, criticized the Syria move.

“If reports about US retreat in #Syria are accurate, the Trump administration has made a grave mistake that will have implications far beyond Syria,” he said on Twitter.

Sitting GOP lawmakers are hesitant to outwardly criticize the president over his willingness to solicit foreign probes of a political rival, because it is the core of the Democrats’ case against him — and almost no issue strikes at Trump so personally as the prospect of becoming the third president in U.S. history to be impeached, according to current and former Republican lawmakers and officials.

Trump, who has two political rallies scheduled for this week, is also likely to campaign heavily against impeachment, putting a spotlight on any Republican who sides with Democrats in criticizing the president’s Ukraine dealings.

“The Ukraine issue is personal, it is a real threat to the president, and a lot of Republicans know they will face his wrath if they defy him,” said former congressman Carlos Curbelo (R-Fla.), a critic of Trump who was ousted in the 2018 midterms. “The issue of our presence in Syria is more obviously a substantive policy issue, where it’s safer to disagree with the president. If Republicans want to be consistent, they should speak out about both.”

Some evangelical Christian leaders aligned with Republicans also condemned the decision, warning that Turkish aggressions in northern Syrian could imperil Christian communities there.

“The president of the United States is in danger of losing the mandate of heaven if he permits this to happen,” Pat Robertson said on the Christian Broadcasting Network’s “The 700 Club.”

No two issues have created a larger chasm between Trump and congressional Republicans than national security and trade, with lawmakers frequently finding themselves battling a president who has often defied traditional GOP orthodoxy.

As the president has exercised his vast executive power in those areas, Republicans have found that they have limited authority to respond.

“The president practices foreign policy,” said former senator Judd Gregg (R-N.H.). As for Republican lawmakers, he said, “they can speak up, but they can’t do anything.”

In tweets Monday morning, Trump defended his decision and said that the United States was being played for a “sucker” by continuing to serve as “a policing operation” for people in Middle East countries “who don’t even like the USA.”

“It is time for us to get out of these ridiculous Endless Wars, many of them tribal, and bring our soldiers home,” he tweeted. “WE WILL FIGHT WHERE IT IS TO OUR BENEFIT, AND ONLY FIGHT TO WIN.”

He also appeared to warn the Turkish government ahead of its offensive.

“If Turkey does anything that I, in my great and unmatched wisdom, consider to be off limits, I will totally destroy and obliterate the Economy of Turkey,” he tweeted.

Republicans quickly began looking at options to counter Trump’s foreign policy decisions. Some pledged to team with Democrats in a rare bipartisan rebuke of the president.

Graham said he spoke with Sen. Chris Van Hollen (D-Md.) and would introduce new sanctions targeting Turkey if Turkish forces invaded Syria.

“Hope and expect sanctions against Turkey — if necessary — would be veto-proof,” he tweeted.

In his statement, McConnell referenced a January vote in which 68 senators rebuked Trump’s threat to withdraw troops from Syria, a large-enough total to override a presidential veto.
“The conditions that produced that bipartisan vote still exist today,” he said.

In a joint statement with Sen. Chris Murphy (D-Conn.), Sen. Mitt Romney (R-Utah) said Monday that he would seek to hold congressional hearings “as soon as possible” on Trump’s decision.

“Barring a reversal of this decision, the Administration must come before Congress and explain how betraying an ally and ceding influence to terrorists and adversaries is not disastrous for our national security interests,” the two senators said.

The White House statement on Sunday announcing the withdrawal appeared to catch even the most senior levels of congressional leadership off guard. Aides to House Speaker Nancy Pelosi (D-Calif.) and Senate Minority Leader Charles E. Schumer (D-N.Y.) said they were not briefed by the administration on the decision. McConnell’s office declined to read out any conversations between him and the president, and House Minority Leader Kevin McCarthy (R-Calif.) said on Fox News earlier Monday that he had planned to speak with Trump about the decision but was not told about it in advance.

While Republican lawmakers have spoken out in uncharacteristically blunt terms against Trump’s Syria policy, history shows they will probably continue to support him, said Russell Riley, a presidential historian at the University of Virginia’s Miller Center.

“That’s the real question: Are the Republicans treating this as a way to inoculate themselves from criticism that they’re lock, stock and barrel with this troubled president, or is this the first step of a declaration of independence from the president?” he said. “I doubt that it’s the latter.”

For their part, Democrats argue that Republican lawmakers do not deserve credit for merely criticizing Trump on policy decisions or his actions and rhetoric.

Sen. Brian Schatz (D-Hawaii) argued that “we’ve lowered the bar as a society and as a Congress for what constitutes demonstrating independence.”

“People get credit for thinking about voting against the president or occasionally not agreeing via tweet,” Schatz said. “But what matters the most as a member of the Senate is how you vote. And no one on the Republican side is using the full power of their office to try to constrain the executive.”