Jesus Christ, the fact that this many posters would support an entirely undemocratic action just because they disagree with the policies of the President. Y'all are some closet Fascists.
It's not about the damn policies, it's about the fact that he is unstable. Not understand why this country cannot use nuclear weapons is not a policy, it is irrational thinking.
1) Assuming Trump is unstable, which he is far from from both a legal and medical standpoint, there's a constitutional way to handle medical incapacity. It's called the 25th Amendment. Nowhere in that amendment does it allow for a third-world style military coup.
2) As the 25th amendment requires a declaration from the executive branch, you're not going to get a sitting President declared mentally incompetent. The shadow cabinet would be running things.
3) The alternative would be impeachment followed by a trial with a conviction on the charges by the Senate.
4) Any talks of a military coup of a duly elected President is un-American. No matter how much you despise him (or her). I would never advocate that for Hillary Clinton, ever.