Their road to victory is simple. Respect the rights of all citizens, meaning they dump their opposition to gay equality. Turn the tables on the Democratic party and make THEM the racists. You either have an open immigration policy, or you don't. If you just allow a single ethnicity to break the rules, then YOU are the racist. There are tens of millions of Chinese and Indians that would line up at the door if we were as soft on them as we are Mexicans. Make it clear your opposition to abortion is a philosophy, and you defer to the Supreme Court on its previous decisions in regards to the matter.
This probably can't even save them, because you are about to see the growth of the Libertarian philosophy when the debt starts reaching into the 20 and 30 trillion range. It will peel a large section of the Republican electorate away. When the debt and budgets get so big, even stealing from the rich isn't enough to pay for them, collapse and ruin is the only outcome. Libertarians will thrive in the aftermath.