Thanedar is not the only Democrat who has signaled impeachment efforts against Trump. But his decision to go it almost alone, without backing from party leadership, comes as he faces his own political challenges at home, with several primary opponents looking to unseat him in his Detroit-area congressional district.

Democratic leaders believe an impeachment vote — destined to fail in the GOP-led House — would be a distraction at a time the party is trying to focus on issues like the cuts to Medicaid that are included in Republicans' sweeping bill for Trump's agenda.