Which third party? The last third party to have any meaningful result was the Reform party, which was pro-choice. As is the Independent party and the Green party. Maybe the Constitution party which got 145,000 votes total in 2004. Or perhaps the Christian Freedom party which in 2004 receved an earth shattering 2,387 votes.
The one that will instantly form if Rudy's the nominee.
Some pro-life, pro-gun voters will support Rudy if he gets the nomination. Maybe a lot of them.
But not enough.