Here Eliot Cohen, formerly of the George  W. Bush Administration, and a longstanding Trump skeptic:

Precisely because the problem is one of temperament and character, it will not get better. It will get worse, as power intoxicates Trump and those around him. It will probably end in calamity—substantial domestic protest and violence, a breakdown of international economic relationships, the collapse of major alliances, or perhaps one or more new wars (even with China) on top of the ones we already have. It will not be surprising in the slightest if his term ends not in four or in eight years, but sooner, with impeachment or removal under the 25th Amendment. The sooner Americans get used to these likelihoods, the better. 

There are enough flippable Republican Senators to join Demomcratcs in convicting Trump of impeachable offenses, but first the House has to impeach, and that will require something Paul Ryan doesn't obviously have:  a spine.  But it's early days, and even Ryan & co. may see the merits of ousting the delusional narcissist.

UPDATE:  A propos Ryan, this is funny.  (Thanks to Roger Albin for the pointer.)