The US Senate rejected a measure aiming to limit US President Donald Trump's war powers, a day after passing a separate resolution that called for the removal of US forces from Iran, late Wednesday evening. 

The measure was proposed by Democratic Sen. Tim Kaine and failed 50-47-1, though GOP Sens. Susan Collins and Lisa Murkowski voted in favor, siding with the Democratic majority. This marks a stark turnaround from Tuesday's resolution.

Both GOP Sen. Rand Paul and Sen. Bill Cassidy voted to limit Trump's power in Iran on the original motion, but changed their votes on the new measure the next day. Paul voted present, and Cassidy voted against the proposition. This comes after Trump called out Congress for limiting his negotiating power with Iran. 

Though the Trump administration claims that the US is no longer involved in attacks on Iran since the MoU and subsequent ceasefire, Kaine's motion called for "the removal of United States Armed Forces from hostilities within or against the Islamic Republic of Iran that have not been authorized by Congress." The measure would've gone to the president's desk for official approval if it had passed, leaving it unclear whether it would've gone into effect.

Trump praised the vote on his Truth Social account, mentioning Sens. Paul and Cassidy for changing their minds and claiming that the measure "puts Iran on notice."

Louisiana Sen. Cassidy has historically called out the president for his lack of transparency regarding US involvement in Iran, culminating in a heated interaction between the two at a private GOP Senate lunch on Wednesday.

"The American people need to know more than we are being told," Cassidy told reporters after the meeting. "It does not appear, although I don't know for sure, that the course of this is going the way that we were told."

Later that evening, Cassidy was invited to the White House for a more conclusive briefing on the situation from Vice President JD Vance and Special Envoy Steve Witkoff. He posted on X thanking the two politicians for "address[ing] many of [his] concerns," and changed his vote in support of the Trump administration that night.

Kentucky Republican Paul also posted on X to clarify his position on the issue. He said that though his opinion hasn't changed, he's voting present "to give the President more space and leverage to negotiate a lasting peace."

The Tuesday resolution heavily reined in Trump's war powers in Iran, seeking to block US military activity in the region. It was the 10th attempt from the Senate to take such action since the US and Israel launched their attack on February 28, and it passed 50-48.

The resolution was approved by the House earlier this month and marked a symbolic show of concern from GOP lawmakers regarding US involvement in Iran. Notably, four republican senators voted in favor of the measure - Sens. Cassidy, Paul, Murkowski, and Collins.

The president took to his Truth Social account following the vote, calling the four Republicans "losers [who] voted with the Dumocrats," claiming that it was "poorly timed and meaningless," and that it indicated to the "Number One Sponsor of Terror in the World that the United States doesn't like what [he's] doing to them."

The Senate rebuked its opposition to the president's war in Iran the next day.

Ruby Sadikman contributed to this report.