What would bring Trump down?

[Frodo]

None of these will stop him from becoming the Republican nominee -but they will seriously damage him in the general election.  The Clinton campaign will not treat him with kid-gloves the way his GOP rivals have up until now.  It will be a scorched earth campaign from the get-go.  

[Frodo]

Since there is a growing belief that Trump will be the nominee, what types of revelations, if any, do you think would bring him down? You can pick up to two choices.

Personally I can only see criminal charges or personal scandals (especially ones which would tarnish his leadership and blue collar-empathy image) doing him in.

Having fathered a child in an extramarital affair with a Muslim woman who's a member of the Socialist Party USA.

A Muslim woman of Afro-Mexican descent. 

[Frodo]

As long as there is breath in his lungs, Trump will almost definitely win the nomination. For better or worse.

The Presidency will be a much harder task. Everything I "know" about reality says he can't do it, but Trump has made a habit of raising a middle digit to reality, turning that middle digit into a knife, and stabbing reality through the heart.

Only because too many GOP candidates treated him with kid-gloves until they realized (too late) what a threat he really was.  Had everyone gone after him last summer, he would not be where he is today.