You make some claims worth considering, though your last one is misleading (”Electing a liberal and expecting him to act as a conservative...” — I never said I was expecting that. What I expect is that Obama will act even worse.)
“Allowing Romney to pull the country further left by appointing liberal justices to SC to replace Kennedy and Scalia, justices who would never retire if Obama is elected, is not a principle I’d wish to support.” I wouldn’t like that either. I think the opposite is more likely, though — that people would settle for a worst nominee from Obama than from Romney because they’d figure that would be the best they can get. As for holding off retirement, yes, those justices might do that, but sometimes death or disability can’t be avoided.
Also I’m not at all sure that after four more years of Obama the right will have enough strength to stage a comeback. I won’t say I expect that Obama will install a regime like the one in Venezuela (though I don’t rule it out under extreme circumstances). I do believe, though, that he’ll take steps to suppress dissent on the right and to undermine our individual freedom that Romney wouldn’t take. As for the military and foreign policy, I’d rather have Romney in charge than Obama.
“a worst nominee” — I meant “a worse nominee”