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.”

He remains the only sitting Republican to openly say that Trump committed impeachable offenses based on his reading of special counsel Robert Mueller’s report.

“Clearly, things that violate the public trust are impeachable,” Amash said Tuesday, drawing applause. “I think it’s really important that we do our job as Congress. That we would not allow misconduct to go undeterred.”

He has not signed on to any existing Democratic impeachment resolutions, but said Tuesday that it would be appropriate for House Speaker Nancy Pelosi to move ahead with an impeachment inquiry.

“She’s very nervous about some of her Democrats who are in what she considers tougher districts,” Amash said to a crowd of more than 700 packed into the Grand Rapids Christian High School auditorium.

“We have a job to do, and I think we owe it to the American people to represent them to ensure that the people we have in office are doing the right thing, are of good character, aren’t violating the public trust.”

Hours before the town hall, Amash had put out a series of 25 tweets expanding on his takeaways from the Mueller report, which explored Russian interference in the 2016 election.

“In truth, Mueller’s report describes concerning contacts between members of Trump’s campaign and people in or connected to the Russian government,” Amash wrote on Tuesday.

Amash singled out Attorney General William Barr for his handling of the report, arguing that Barr had misrepresented Mueller’s findings, including in testimony before Congress.

“Barr has so far successfully used his position to sell the President’s false narrative to the American people. This will continue if those who have read the report do not start pushing back on his misrepresentations and share the truth,” Amash tweeted.

The congressman is known for his independent streak and has a history of splitting with conventional GOP positions on controversial topics, such as surveillance and foreign policy.

His criticism has made him a target for Trump – the President recently said Amash has “been a loser for a long time” – and has drawn the primary challenge in his Grand Rapids-area district, which he has represented since 2011.

During the event, one constituent asked why Amash hadn’t declared as an independent yet. “The system we have in Michigan makes it very difficult to run as an independent,” Amash responded, pointing to straight-ticket voting and signature requirements to get on the ballot.

A potential third-party presidential bid also came up during the event; Amash again declined to rule out running for president in 2020, or any other higher office, though he did say his impeachment stance wasn’t the way he would roll out such an effort.

“In life, if you’re fighting to defend the Constitution and you find a way to do it that’s different and more effective, then you have to think about that,” he said.

CNN’s Alison Main contributed to this story.