Close video Republican calls for impeachment after reading Mueller report Rachel Maddow reports on how actually reading Robert Mueller’s Trump-Russia report convinced Republican congressman Justin Amash of the need to impeach Donald Trump, and to speak out about his conclusions despite considerable blowback from Trump and his Rachel Maddow reports on how actually reading Robert Mueller’s Trump-Russia report convinced Republican congressman Justin Amash of the need to impeach Donald Trump, and to speak out about his conclusions despite considerable blowback from Trump and his share tweet email Embed

For eight weeks, it was notable that one – and only one – Republican member of Congress publicly supported Donald Trump’s impeachment.

On the 4th of July, however, that number slipped back to zero – not because a member of Congress reversed course on the impeachment question, but because the GOP lawmaker in question decided it was time to abandon his party.

Michigan Rep. Justin Amash announced Thursday that he was leaving the GOP after growing “disenchanted” and “frightened” by party politics. Amash, who represents Michigan’s third congressional district, wrote in an op-ed for The Washington Post that he would remain in Congress as an independent.

The lawmaker’s announcement came less than a month after Amash also parted ways with the right-wing House Freedom Caucus, which he helped create.

In light of these high-profile shifts, it may be tempting for some to assume that the Michigan congressman is shifting his ideology, or perhaps even becoming more moderate, leaving him out of place with the increasingly far-right Republican mainstream. But that’s not quite right: Amash has changed his affiliations, but not his political perspective or principles.

Or put another way, as far as Amash is concerned, he didn’t leave the GOP; the GOP left him.

It’s exceedingly rare for sitting members of Congress to change parties, which made Amash’s announcement extraordinary in its own right, but there are also some meaningful practical implications of news like this.

Right off the bat, the House Republican conference will shrink to 197 members (a number that may yet inch higher after a couple of upcoming special elections in North Carolina). Once the partisan divorce is official, House GOP leaders will likely strip Amash of his committee assignments, including his seat on the Oversight Committee.

What’s more, the race in Michigan’s 3rd congressional district, which Amash has represented for the last decade, just became considerably more complex. If the incumbent seeks re-election – by no means a certainty – Amash will apparently have to run as an independent or a member of a third party, while Republicans and Democrats field their own contenders in a relatively competitive district.

And then, of course, there’s the 2020 presidential race. In recent weeks, the Michigan lawmaker has fielded a series of questions about running for the White House as the Libertarian Party’s nominee, and in each instance, Amash has left the door open. Yesterday, he sat down with CNN’s Jake Tapper, and Amash again said he “still wouldn’t rule” out a presidential run.

It’s far too soon to speculate with any confidence about the implications of such a candidacy – who’d benefit, where Amash would compete, what it would mean for Trump, etc. – but if you thought the 2020 race was already complex, it may soon get a dramatic twist.