Former Rep. Adam Kinzinger (R-Ill.) hammered Donald Trump on Thursday night, accusing the former president of threatening American democracy and destroying the Republican Party as he knew it.

In a prime-time speech delivered shortly before Vice President Harris took the stage, Kinzinger denounced Trump’s role in the Jan. 6, 2021, attack on the U.S. Capitol and accused his supporters in the GOP of abandoning the basic tenets of conservatism that had guided the party for decades before Trump’s arrival.  

“The Republican Party is no longer conservative,” Kinzinger said. “It has switched its allegiance from the principles that gave it purpose to a man whose only purpose is himself.”

Kinzinger was once a Trump supporter and rising GOP star, closely allied with former House GOP Leader Kevin McCarthy (Calif.) for most of his six years in Congress.

But the Jan. 6 attack inspired a change of tune. Kinzinger was one of the 10 House Republicans to vote for Trump’s second impeachment, and he joined the select committee, formed by then-Speaker Nancy Pelosi (D-Calif.), to investigate the attack.

The panel found that Trump was responsible for orchestrating the attack. And on Thursday Kinzinger minced no words in denouncing the former president as a con man who has “suffocated the soul of the Republican Party.”

“Donald Trump is a weak man pretending to be strong,” Kinzinger said. “He is a small man pretending to be big. He’s a faithless man pretending to be righteous. He’s a perpetrator who can’t stop playing the victim.”