WASHINGTON — The seed for Senator Bill Cassidy’s decision to find Donald J. Trump guilty of inciting an insurrection was planted one day last fall, when he received an email from a friend that was full of the then-president’s false claims about a stolen election.
Alarmed that Mr. Trump’s lies were gaining credence, Mr. Cassidy, a Louisiana Republican, became part of a small minority in his party — and one of only a few officials in the South — to acknowledge President Biden’s victory. Months later, after Mr. Trump’s campaign to overturn the election culminated in the Capitol riot, Mr. Cassidy was one of only seven Republican senators who voted on Saturday to convict him.
Taken at face value, Mr. Cassidy — a conservative, newly re-elected physician with a quirky streak — has little in common with the other six senators who broke with their party and found Mr. Trump guilty in the most bipartisan vote for a presidential impeachment conviction in United States history. Most were facing intense backlash on Sunday from Republicans in their states livid about the vote, as have the 10 House Republicans who supported the impeachment last month.
But the senators were united by a common thread: Each of them, for their own reasons, was unafraid of political retribution from Mr. Trump or his supporters.
“Two are retiring, and three are not up until 2026, and who knows what the world will look like five years from now,” said Whit Ayres, a veteran Republican pollster. “It looked pretty different five years ago than it did today. All seven of them have a measure of independence that those who have to run in 2022 in a closed Republican primary just don’t have.”
For Mr. Cassidy, it was a sense of outrage at the former president’s actions, starting long before the assault on Jan. 6, that played the dominant role. In an interview on Sunday, Mr. Cassidy said Mr. Trump had “trumpeted that lie” about the election for months, then sat by for hours as lawmakers and his own vice president were under attack in the Capitol and did nothing — other than to call Republican senators to ask them to continue challenging the election results.
“That anger simmers in the background,” Mr. Cassidy said. “My whole life, reading about great men and women who sacrifice for our country, who sacrifice so that we could have the freedoms that we have here today — and the idea that somebody would attempt to usurp those and destroy them?”