Grand Rapids, Michigan (CNN) Republican Rep. Justin Amash of Michigan may have been prepared to deal with critics at his first town hall since publicly stating earlier this month that President Donald Trump has engaged in impeachable conduct, but instead he got a standing ovation Tuesday.

Attendees even booed and heckled a woman in a Make America Great Again hat who defended Trump, prompting Amash to step in. "Let's be respectful," he urged the crowd.

During the town hall, which went on for two hours, an hour longer than planned, Amash defended his conservative credentials -- "I'm who I said I was. I'm a principled, constitutional conservative" -- and once again brushed off a new primary challenge from Michigan state Rep. Jim Lower.

"I am not concerned about it," Amash told the crowd, adding: "And in any case, you should always do what's right."