'The arguments were strong': Louisiana Republican changes his mind — declares impeachment constitutional
Sen. Bill Cassidy (CNN)

One of the biggest obstacles to Democrats earning the required 17 Republican votes to convict former President Donald Trump is that the vast majority of Senate Republicans have made up their mind that impeaching a former president is unconstitutional — a legally questionable claim, especially considering that Senate GOP Leader Mitch McConnell (R-KY) made a political decision not to hold the trial while Trump was still in office.

When Sen. Rand Paul (R-KY) introduced a resolution to declare the whole trial invalid two weeks ago, only five Republicans sided with Democrats to vote it down: Sens. Lisa Murkowski (R-AK), Susan Collins (R-ME), Ben Sasse (R-NE), Pat Toomey (R-PA), and Mitt Romney (R-UT).

However, on Tuesday, when the Senate held a vote to officially declare the trial constitutional after a day of legal arguments, one extra Republican senator who had backed Paul's resolution, crossed over to vote in favor of the trial: Sen. Bill Cassidy (R-LA).

Speaking to reporters, Cassidy explained that he had been swayed by the House managers' arguments. "I'm trying to digest facts," he said. "And I thought the arguments they gave were strong arguments."

Cassidy's vote on the procedural grounds is not a guarantee he will ultimately vote to convict Trump on the merits. Also, Democrats would need at least 11 votes from Republicans who voted no on Tuesday to secure a conviction.