A day of debate on whether it is constitutional to put a former president on trial in the Senate succeeded in changing the mind of one senator. Donald Trump's second impeachment trial was declared constitutional in a 56-44 vote, with six Republican senators voting with the chamber's 50 Democrats. Last month, five Republicans voted against dismissing the trial. On Tuesday, GOP Sen. Bill Cassidy of Louisiana flipped and said he believes the trial is constitutional, the Hill reports. He was joined by Republican Sens. Susan Collins, Lisa Murkowski, Mitt Romney, Ben Sasse, and Pat Toomey, who voted the same way last month. "I have always said I was approaching this with an open mind," Cassidy said, per the AP. He said the House impeachment managers delivered "strong arguments." (More Trump impeachment stories.)