From the 25th amendment…
Whenever the Vice President and a majority of either the principal officers of the executive departments or of such other body as Congress may by law provide, transmit to the President pro tempore of the Senate and the Speaker of the House of Representatives their written declaration that the President is unable to discharge the powers and duties of his office, the Vice President shall immediately assume the powers and duties of the office as Acting President.
So, if Trump sufficiently pisses off Pence and a majority of the Cabinet (or if they just tire of being ridiculed), a quick note to Congress and Trump’s out.
I agree with Mr. Krugman: Trump’s nuts. But none of the GOPer congresscritters have the testicular fortitude to start up the impeachment machine. The 25th seems (to me) to be an easier and quicker alternative.
The amendment specifies that Trump could say “Hey! I’m not nuts!” and then Congress would have to vote on it. If 2/3 of both houses say “Sorry, but you really are nuts” then say Buh-bye to the Orange Shitgibbon.