I still wouldn't bet on impeachment. The rival party controlled Congress during the Clinton and Nixon episodes, but Republicans now hold clear command of both houses. Republicans can't win elections without Trump voters, and must take great pains to avoid any impression of betrayal. They are already more than suspect on this score, and pushing too hard could tear the party apart into pro- and anti-Trump factions.
But it's getting difficult to imagine things continuing like this for much longer.
I wouldn't be surprised if the more responsible Republicans are trying to think of face-saving ways for Trump to be persuaded to "resign." Anyways, he can't be having much fun anymore, now that the rush from the toys and the pomp of the Presidency have given way to worldwide ridicule and humiliation.
Resignation, perhaps "for health reasons," would probably be the smoothest solution.
Trump supporters are a frustrated and angry bunch, armed to the teeth, and often bearing only tenuous connections to reality. Thus, whatever its legal basis, impeachment would be an extremely risky endeavour. In the eyes of a significant, volatile minority, the legitimacy of the entire edifice could be forever compromised (if it hasn't already:
https://www.theguardian.com/world/2...tizens-rightwing-terrorism-hate-us-government). A subsequent surge of fringe right-wing terrorism, like this
https://newrepublic.com/article/142...i-muslim-refugee-murder-plot-trump-supporters (and many other examples) might even follow. And even at best, a significant portion of the population would be left irreconcilable.
The fundamental legitimacy of any legal or political system is always more important than the observation of individual component principles. If Democrats are going to indulge in the idea of impeachment, regardless of its legal merits, they'd better have a very clear plan which anticipates these consequences (and if the last two years have taught us anything, it's that they don't do clear plans). Absent a clear popular consensus, it will be profoundly if not irrevocably divisive, and possibly even very dangerous.
Or, absent deus ex machina Islamic terror, the GOP could always try going to war again! It gave George W. a dead cat bounce long enough to secure the second term: