It is a real possibility. Right now, the GOP is run by fiscal liberal/social conservative politicians. This is out of step with most of the party, but the other option is the fully liberal democratic party.
The emerging power center in US politics are the fiscal conservative/social moderate groups such as the small "l" libertarians and the "South Park republicans". These groups vote GOP now, but as the party goes further to the left on fiscal matters and further to the right on social matters (morality police), the Libertarian party will look more attractive.
Hopefully these groups can convice the big "L" Libertarians to adopt realistic stances on national defense and border patrol. The party has it wrong now, but so does every other party.
Unfortuately, we are going to have to have power shift to the democrats to get the attention of the GOP. A lot of damage can be done in four years, but it is a short amount of time compared keeping the current incarnation of the GOP in power.
In other words the "Libertarian Party" should stop being "libertarian." Since the republicans are the only people with "realistic stances," all libertarians should now switch and become republicans in the new non-libertarian republican Libertarian Party.
Hmmm.... and you believe this?
Unfortunately, we don't have the time. How many nukes could be smuggled into the country in 4 years of Hitlery? How many cities are you willing to see wiped off the map?
It doesn't have to come to that. Constitution and Libertarian Party members could use the GOP to their advantage, if they were wise.
How many people here realize just how mortally wounded the Democrat Party is? The party of the jackass is dying and aborting itself like there is no tomorrow. And rightist third parties can deliver the death blow once and for all if they use the GOP, then split off.
America is a two-party system. The only question is which two parties will there be?