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.
While I agree with you, I wasn't thinking so much about a process or even another candidate who could bring Trump down (although that warrants a separate discussion)
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The intent of the poll was to see what type of revelation (if any) would affect Trump's popularity and dissuade his supporters (i.e. To the point where Trump would start hemorrhaging support)!!