For a Republican smear to be effective though, it doesn't have to be true. Just plausible enough for gullible people who want to believe it, to rationalize and justify their prejudices and vote against the guy (in this election, Obama).

This is page 1 of the Republican play book. It doesn't do a damn thing to stand around wringing hands over it. Obama has to find a way to hit back, hit back hard, and hit back negatively.

Will that destroy his brand? No one, including the Obama camp, knows for sure. But what is known for sure, is if Obama isn't willing to go negative against McCain, hard and fast, he could easily lose in November.