(CNN) Rep. Justin Amash, the Republican-turned Libertarian who briefly mulled a presidential campaign earlier this year, said Thursday that he will not run for reelection to his US House seat.
"I love representing our community in Congress. I always will. This is my choice, but I'm still going to miss it. Thank you for your trust," he wrote.
Amash told CNN last month that he paused campaigning for his House seat while he considered running for president, and that even after he chose not to launch a White House bid, his House campaign remained suspended.
Amash has represented Michigan's 3rd Congressional District since he was first elected in 2010.
He is the son of a Syrian immigrant mother and a Palestinian refugee father. Before entering Congress, he worked as a lawyer for his family's business and served a term from 2008-2010 in the Michigan state house.
Amash began in the House as a Republican, but he was always willing to split from the GOP leadership and the party orthodoxy on issues including war powers, foreign policy and surveillance.
He helped establish the conservative House Freedom Caucus, which clashed with Republican leaders and pushed to open up the legislative process and limit federal spending.
Amash grew disenchanted with the group during the Trump era. Leading Freedom Caucus members, including now-White House chief of staff Mark Meadows and Ohio Republican Jim Jordan, became some of the most outspoken defenders of the President, even as Amash continued to be one of the few Republicans willing to question him.
"From the time the President was elected, I was urging them to remain independent and to be willing to push back against the President where they thought he was wrong," Amash told CNN last year. "They've decided to stick with the President time and again, even where they disagree with him privately."
Amash chose to step down from the Freedom Caucus after he became the only congressional Republican to support impeaching President Donald Trump on the basis of Robert Mueller's report on Russian interference in the 2016 election.
Last July, he announced his departure from the Republican Party as a whole.
In a Washington Post op-ed decrying the two-party system, Amash wrote that "preserving liberty means telling the Republican Party and the Democratic Party that we'll no longer let them play their partisan game at our expense."
For more than a year afterward, Amash refused to rule out the possibility of a presidential bid. This spring, he said he was exploring a run as a Libertarian candidate, before ultimately deciding against it.
He said he concluded that "circumstances don't lend themselves to my success as a candidate for president this year," but he expressed optimism that a "candidate from outside the old parties, offering a vision of government grounded in liberty and equality, can break through in the right environment."