If Romney doesn't win I doubt I will ever vote Republican again. Scenarios:
1. The Republican Party started as a 3rd Party. There is no reason the TEA Party and others could not transform into a viable 3rd Party and turn the Republicans into the next Whig Party.
2. Israel could attack Iran before the election and Obama could broker a 7 year peace treaty between Israel and the other warring parties. Obama becomes everyone's hero and wins in a landslide election. The biggest problem with this scenario is that the first no-doubt-about-it,-not-subject-to-interpretation thing that the Antichrist does is impose a 7 year covenant with Israel. But don't worry, Jesus wins in the end!