Sen. Rand Paul (R-KY), one of Congress’s most prominent non-interventionists, blocked a move on Thursday to bring a House-approved measure formally condemning President Donald Trump’s withdrawal of U.S. troops from northern Syria.

Senate Minority Leader Charles Schumer (D-NY) attempted to gain consent to introduce the measure to the upper chamber’s floor, but because it requires unanimous consent, any senator has the ability to thwart it.

“The most important thing we can do right now is send President Trump a message that Congress, the vast majority of Democrats and Republicans, demand he reverse course,” Schumer said.

Paul argued Schumer was attempting to circumvent the U.S. Constitution by bringing the measure to a vote.

“He should come to the floor and say that we are ready to declare war. We are ready to authorize force, and we are going to stick our troops in the middle of this messy, messy, five-sided civil war where we would be ostensibly opposed to the Turkish government that has made an incursion,” he said.

The House had passed a resolution Wednesday condemning President Trump’s decision to withdraw U.S. troops from Syria in a 354-60 vote.

The move by Paul comes as U.S. officials said Turkish President Recep Tayyip Erdogan has agreed to stop its offensive in Syria, signaling an end to a military campaign that has so far killed dozens of Kurdish fighters and drawn international condemnation.

Vice President Mike Pence announced the agreement for a five-day cease-fire after hours of bilateral meetings in Ankara among U.S. and Turkish officials — which included Erdogan and Secretary of State Mike Pompeo. The situation will be re-evaluated at the end of the five-day deal.

Erdogan’s forces began Operation Peace Spring a week ago in northeast Syria, to clear border territories of Kurdish fighters so Ankara can send back Syrian refugees who fled to Turkey. The Turkish leader has previously insisted he would accept no cease-fire.

“The United States and Turkey have both mutually committed to a peaceful resolution and future for the safe zone, working on an international basis to ensure that peace and security defines this border region with Syria,” Pence stated.

The UPI contributed to this report.