(CNN) Michigan Republican Rep. Justin Amash's weekend tweets suggesting that President Donald Trump had committed "impeachable conduct" drew lots of headlines. The reason? Because he was a lone voice in the wilderness. And it's very, very likely to stay that way.
The reason is simple: It's bad politics for Republicans to break with Trump. Even on an issue as serious as possible obstruction of justice of a probe into Russia's interference in the 2016 election.
Amash's break with Trump (and the President's allies) on impeachment isn't totally new ground for the fourth-term member of Congress, who holds a district that Trump won with 51% in 2016. In that presidential race, Amash, a self-proclaimed libertarian, endorsed Sen. Rand Paul of Kentucky and then Sen. Ted Cruz of Texas. Amash neither supported nor voted for Trump. (His issues with the President are focused on the expansion of executive power and the rising debt.)
"I view my job as being the representative for everyone in the district, regardless of political party," he told a local newspaper following the 2016 election. "I will take positions that sometimes the political establishment -- my own party -- won't like. I will take positions that sometimes the Trump administration won't like. And sometimes I will take positions that the Democrats won't like. My job is to be fair."
Which feels like the sort of thing we would all want our representatives to say, right? Except, in this moment in politics among Republicans, disloyalty to Trump is punished. And the jury, judge and, often, executioner of your political life is the President himself.
Trump, via Twitter, blasted Amash as "a total lightweight who opposes me and some of our great Republican ideas and policies just for the sake of getting his name out there through controversy."
By the close of the weekend, state Rep. Jim Lower had announced he was going to challenge Amash in next year's Republican primary. "Congressman Justin Amash's tweets yesterday calling for President Trump's impeachment show how out of touch he is with the truth and how out of touch he is with people he represents," Lower told the Detroit Free Press. "He must be replaced and I am going to do it."
It remains to be seen how serious Lower's challenge will be. But if past is prologue, Amash has reason to be nervous. In 2017, Arizona Sen. Jeff Flake (R) emerged as one of the GOP's leading critics of Trump -- and his own party's capitulation to the billionaire businessman. Trump went after Flake. Flake's poll numbers cratered. He was forced to retire. While Flake's colleague Sen. Bob Corker wasn't forced out in quite the same way, there's no doubt that his criticism of Trump -- and the President's reaction to it -- hurt his poll numbers as he considered running again in 2018. (Corker retired; Republican Marsha Blackburn claimed his seat easily.)
The message here for Republicans weighing a public break with Trump on impeachment (or anything else) is clear: Raise your head up and watch him chop it off. (RIP, Missandei.)
And the simple truth of politics is that most politicians value keeping their jobs -- and the possibility of higher office in the future -- over everything else. Standing by your principles sounds good! But when the rubber meets the road and standing by your principles also badly endangers you politically, most politicians swallow those allegedly foundational principles.
That is not to say that every Republican who hasn't said Trump acted in ways that are "impeachable" (so, all of them except Amash) is doing so purely out of political expediency. Many believe that while Trump didn't act as they would in the same situation, he didn't actually obstruct the special counsel investigation led by Robert Mueller.
But it is equally true that if there were no -- or minimal -- political consequences to speaking out against Trump, there would be lots (and lots) more GOPers like Amash stepping forward. But with the President at 90% approval among Republicans, according to the latest Gallup national poll, there's zero incentive for any wavering Republicans to step forward and stand beside Amash. In fact, there's a disincentive since not only will the Republican base likely turn against you, you won't win over Democrats with such a move because Trump has so polarized both sides of the political world.
And so, Amash is likely to be a man apart -- and unfollowed. He may come into praise from some Republicans for his principled stand, but those same Republicans won't follow him out on that limb. (Looking at you, Mitt Romney!) But add up all that praise for principles and you get exactly squat.