Three theoretical ways Republican can get their President other than Trump

[MASHED POTATOES. VOTE!]

Since the forum is big on wild speculations.

1. That one's been probably mentioned here already. McMullin wins in Utah and there's no majority in the EC. The House GOP leaders maneuver to elect a third placer in electoral vote, that is McMullin.

2. No majority in the EC, but Republicans controls Senate and elects Pence VP. Thus Pence becomes Acting President on January 20.

3. The most unlikely of these unlikely scenarios. By a fluke of the Gods neither House nor Senate are able to elect President and VP respectively. That leaves Paul Ryan as Acting President on January 20. 

[Beefalow and the Consumer]

If it falls on the House to elect the President, they will elect Trump.  Period.

GOP leaders aren't objecting to Trump because he's a deplorable human being who incites hatred, abuses women, and flirts with the idea of challenging the result of a fair and open election.  GOP leaders are objecting to Trump because they think he's going to lose bigly, and they don't want to go down in flames with him.  If Trump suddenly surged to 10 points ahead, Paul Ryan would be falling over himself to get on the Trump Train again.

In theory some maverick Republicans could tie up enough states to keep Trump from being elected, but they would need to switch parties afterwards, because their career as Republicans would be over.

[MASHED POTATOES. VOTE!]

I agree. It would be extremely hard for a House Republican to justify voting against their party candidate after Trump won millions of Republican votes across the country.

So it's pretty much very theoretical.