I look at it like this:
1)Romney wins and they cry foul. We point out how they basically said the only acceptable result is an O win, and their allegations mean about as much as a fart in a tornado, and tell them to pound sand.
2) They try to file suit in court. We claim they have no standing since they are not citizens and have no rights under the Constitution to influence our form of government, and tell them to pound sand.
3) They try to sanction the US for voting improprieties. We cut off funding and tell them to pound sand.
4) They threaten "regime change" through military means. We tell them to bring it, the US army has had 10+ years of combat training and American citizens have 50M+ privately owned weapons.