If Cain is somehow strong enough to win the GOP nomination, then I suspect he may be strong enough to win the presidency.
This couldn't be farther from the truth. If Cain somehow manages to win the nomination, it will be because 51% of Republican primary voters are disgusted with Romney and Perry and voted for the anti-politician Cain in protest. The general election has an entirely different audience. You have to appeal to moderates and independents. You have to be non-controversial and act presidential. Cain has all of the qualities that make him appealing to conservative Republicans, but none of the qualities that instill confidence among swing-voters.
Cain cannot win the GOP nomination simply because he is not Romney. Cain is doing well because he has incredibly strong positive to negative ratio, something which I simply do not understand.
In any case, Cain's ideology is not nearly as important as whether or not he is seen as a more capable leader than Obama. That's what this election will be about. If this country wasn't comfortable electing conservative candidates, then it wouldn't have done so in 1980, 1984, 2000, or 2004.