Former Rep. Justin Amash has jumped into the Republican primary race for Michigan‘s open U.S. Senate seat, a race that could decide the Senate majority in a battleground state that also could determine the outcome of November’s presidential election.

A political turncoat and supporter of former President Donald Trump‘s first impeachment, Amash represented Michigan’s Grand Rapids-anchored 3rd Congressional District as a Republican, an independent, and then as a Libertarian during the decade he was in the House before he retired in 2021. His announcement spices up the GOP primary as the party had started coalescing behind former House Intelligence Committee Chairman Mike Rogers.