Republican senators have blocked a largely Democratic-led amendment that aimed to restrict President Donald Trump’s authority to militarily strike Iran without first obtaining congressional approval.

During a voting session on Friday, the proposal by Democratic Sens. Tim Kaine and Tom Udall was rejected 50 to 40, but for the amendment to be added to the National Defense Authorization Act (NDAA), supporters needed 60 yes votes.

“We must tell the president and affirm to the American people that we will assume our constitutional responsibility,” said Udall, Democrat of New Mexico. “And we must do so now before — through miscalculation, mistake or misjudgment — our nation finds itself in yet another endless war.”

Senate Minority Leader Charles Schumer (D-N.Y.) also told reporters that “the American people are very afraid that this president, even if he doesn’t want to start a war, would bumble us into one.”

Tensions increased between the US and Iran after the Islamic Revolution Guards Corps (IRGC) shot down an intruding American spy drone in the country’s southern coastal province of Hormozgan on June 20.

Following the downing of the RQ-4A drone, Trump claimed he had called off US strikes on three different Iranian sites 10 minutes before they were planned to be launched.

A few days later, the White House introduced new sanctions that targeted Leader of the Islamic Revolution Ayatollah Seyyed Ali Khamenei and senior commanders of Navy, Aerospace, and Ground Forces of the IRGC.

Washington is also set to slap bans on Iranian Foreign Minister Mohammad Javad Zarif, who is seen as the architect of a 2015 multilateral nuclear deal, which Washington abruptly abandoned last year. The US reinstated its unilateral sanctions against the Islamic Republic following its exit from the landmark deal.