What would bring Trump down?

[Fuzzy Bear Loves Christian Missionaries]

Short of a criminal indictment, it would be hard to stop Trump without creating the elements needed for a brokered convention.  This is possible, but it would put the GOP in the position of (A) airing much dirty linen in public and (B) denying the candidate with the most popular support in the primaries and caucuses the nomination in favor of either someone who was rejected by the voters, or by a candidate that was "airlifted" into the convention to break a deadlock.