I have a feeling that this won't end well--all conceivable outcomes, short of rescue by benign alien intelligence, range from grim to smoking pile of nuclear rubble.
In the event of Trump's vacating his office (either through impeachment, resignation, the 25th amendment, or even death) Ayatollah Mike Pence officially takes control, though if you have been paying attention, he has been lurking everywhere there has been yet another Trump disaster. Pence, a misogynist, self-righteous, right wing ideologue responsible for imprisoning women for abortions and increasing the incidence of HIV infection in his state, has never met a woman he can dine with, a rich person (who isn't a liberal) he won't suck up to, or a poor person who he thinks is entitled to medical treatment. This unctuous creep, with the smooth mien of a christian talk show host will continue to carry out the devastating war-on-Americans-who-aren't-millionaires policies he has quietly pushed while Trump sits in the Oval Office.
If Pence seems vulnerable to the same impeachable charges that Trump does (and as I said, his fingerprints are everywhere) then waiting in the wings is smarmy liar Paul Ryan, someone whose opinion of his own acumen is as great as his actual knowledge deficits. If you think he would step aside to make room for next in line, President Pro Tempore of the Senate Orrin Hatch, you haven't been paying attention. But if somehow the office passes to the next in line, we get the bumbling Rex Tillerson. In any event, the demolition of the American republic to make more room from the growing class of kakocrats will continue apace.
And this scenario (Trump gone) is on the positive end of the spectrum of horrible likely outcomes. On the extreme negative side? A smoking pile of nuclear rubble. And if you think that Trump isn't considering a preemptive strike on North Korea to distract from his current troubles, I'd like to have some of what you are smoking.