Obama's going to have a hard time explaining that I take to be the truth, namely that his relationship with Trinity has been a bit cynical from the beginning. After all, before Obama was a half-black guy running in a mostly white country he was a half-white guy running in a mostly black neighborhood. At that time, associating with a very large, influential, local church with black nationalist overtones was a clear political asset (it's also clear in his book that it made him, personally, feel "blacker" to belong to a slightly kitschy black church). Since emerging onto a larger stage, it's been the reverse and Obama's consistently sought to distance himself from Wright, disinviting him from his campaign's launch, analogizing him to a crazy uncle who you love but don't listen to, etc. The closest analogy would probably be to Hillary Clinton's inconsistent accounting of where she's from (bragging about midwestern roots when trying to win in Iowa, promptly forgetting those roots when explaining away a loss in Illinois, developing a sporadic affection for New York sports teams) — banal, mildly cynical shifts of association as context changes.
This is why I don't, as an American citizen, worry that President Obama would be objectionable. But Americans take their religion seriously and aren't going to want to hear this story. So Obama's going to have to do some awkward further distancing.
Yglesias may well be correct about Obama, but when you're left with the choice of either acknowledging that you had sincere close, personal, and political ties with a minister whose views most Americans find beyond the pale, or defending yourself by using the "hey, I'm just a cynical politician who uses religion to get votes just like anything else, and I don't believe in it any more than I really believe that NAFTA is bad" excuse, I think you may be in for some trouble.
UPDATE: An anecdotal report from my father from discussions with congregants after Friday night's service at a Reform synagogue in the Poconos in Pennsylvania: the congregants have turned against Obama because of Wright, and think McCain is a warmonger. Strong support for Clinton.