President Donald Trump changed the conversation from impeachment — at least for a day — with his move to abruptly withdraw U.S. forces from Syria. But he also opened a front with Congress that may prove unsustainable.

From steadfast GOP allies and liberal Democrats backing an impeachment inquiry, the blowback to Trump is coming from all angles, suggesting a real bipartisan pressure campaign that could force the president to reverse himself.

Senate Majority Leader Mitch McConnell (R-Ky.) is reminding Trump of supermajorities supporting a U.S. presence in Syria. Sen. Lindsey Graham (R-S.C.) is threatening sanctions against Turkey in partnership with Sen. Chris Van Hollen (D-Md.). And a bipartisan pair of Senate Foreign Relations Committee members are demanding administration officials testify before Congress.

“The president’s decision to abandon our Kurdish allies in Northern Syria in the face of an assault by Turkey is a betrayal that will have grave humanitarian and national security consequences,” said Sens. Mitt Romney (R-Utah) and Chris Murphy (D-Conn.). “We will be working with committee leadership to assure that the administration appears before the committee as soon as possible.”

The Republican Senate has already shown a willingness to confront Trump on Syria and other foreign policy matters, and the gears are quickly turning in Congress to force Trump to back down.

Graham said Monday he will put forward a Senate resolution asking Trump to change course, predicting it “will receive strong bipartisan support.” In February, 70 senators supported a nonbinding amendment backing U.S. operations in both Syria and Afghanistan.

Lawmakers will also have multiple chances to weigh in on Trump’s foreign policy in the coming weeks and months, as Congress must pass its annual defense legislation as well as spending bills to fund the government.

In a rare statement chiding Trump, McConnell referenced the amendment adopted earlier this year, noting “the conditions that produced that bipartisan vote still exist today.”

“ISIS and al Qaeda remain dangerous forces in Syria and the ongoing Syrian civil war poses significant security and humanitarian risks. A precipitous withdrawal of U.S. forces from Syria would only benefit Russia, Iran, and the Assad regime,” the GOP leader said. “I urge the president to exercise American leadership to keep together our multinational coalition to defeat ISIS.”

Not far behind came a statement from Speaker Nancy Pelosi that echoed the Kentucky Republican: “This decision poses a dire threat to regional security and stability, and sends a dangerous message to Iran and Russia, as well as our allies, that the United States is no longer a trusted partner.”

Trump signaled that he heard the bipartisan condemnation loud and clear. Yet he remained unbowed, even as he sought to address the criticism. He told reporters he wants to wind down “endless wars” and that he had told Turkish President Recep Erdoğan not to do anything that’s “not humane” to the Kurds.

“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,” the president tweeted. “The U.S. has done far more than anyone could have ever expected, including the capture of 100% of the ISIS Caliphate. It is time now for others in the region, some of great wealth, to protect their own territory.”

Republicans in Congress have shown a willingness to challenge Trump on foreign policy in a way they haven’t over most domestic issues or the president’s inflammatory rhetoric and controversies.

And the sheer volume of criticism from Capitol Hill suggests this move on Syria is even more offensive to the GOP. Other than Sens. Rand Paul (R-Ky.), Mike Lee (R-Utah) and Rep. Matt Gaetz (R-Fla.), there were almost no members of Congress defending the president on Monday.

”Congress has never declared war or authorized the use of military force in Syria,” Lee said in a statement. “While I remain concerned with Turkey’s behavior and the threat they pose to the Kurds, I support President Trump’s decision to draw down U.S. armed forces from Syria.”

Senate Foreign Relations Chairman Jim Risch (R-Idaho) has not commented on Trump’s Syria shift yet. He said though a spokesman he will “have a statement in due course.”

“My staff and I are speaking with the administration and interested parties to fully understand intentions and potential consequences,” said Risch, who has defended Trump in the past on controversial foreign policy moves.

Trump has faced several bipartisan challenges to his administration’s relationship with Saudi Arabia after the killing of journalist Jamal Khashoggi, but opposition from McConnell has kept votes to restrict arm sales to Saudi Arabia and the U.S. involvement in Yemen’s civil war short of a veto-proof majority.

The Senate GOP leader’s support for reversing Trump’s Syria policy suggests the president could be overpowered by Congress or at a minimum face a devastating fight with the Republicans he is counting on to keep him in office if the House impeaches him.

And the challenge from Graham could prove equally problematic. Despite his loyalty to Trump, he enjoys strong relationships with some Democrats, affording him a bipartisan perch to challenge Trump’s foreign policy decisions.

After Trump explained that he’d be willing to retaliate against Turkey if it goes after the Kurds, the hawkish Graham continued his fusillade against the president — needling Trump with a comparison to his predecessor’s foreign policy, which has long been reviled by conservatives.

“No matter what President Trump is saying about his decision, it is EXACTLY what President Obama did in Iraq with even more disastrous consequences for our national security,” Graham tweeted. “Unlike President Obama, I hope President Trump will reassess and take sound military advice.”