Sanford is an immoral pig. Voters abandoning their principles doesn't change that nor does it make them "winners". They just wallow in slop with their "choice". Lay down with dogs, get up with fleas.
You put yourself in a trap, sorry. You wouldn’t vote for a man whose family can’t trust him. You can not prove that Obama’s family can’t trust him. Therefore you trust Obama more than Sanford. And equally therefore, you would vote Democrat rather than vote for Sanford. In essence your answer is “What difference does it make?” if you wallow with Democrats or immoral Republicans. You get fleas and ticks either way. So, wallow with the Democrats.