Then one of two things happen, neither of them good.
1. A third party candidate from the right runs and splits the conservative vote and Obama coasts to his second term
or
2. Romney somehow manages to keep the party together and wins, but then resorts to his RINO ways reforming absolutely nothing
Option two is probably actually the worse one because the economy won't get any better, and the GOP will get the blame. This will damage the party and our cause even more than Compassionate Conservative Bush did.