Disagreement.

Dear Ms. Lindsay King,
Please don't worry about whom celebrities endorse. If they get any attention, it's because they're fighting a losing battle for the nomination, like Oprah with Obama and Chuck Norris with Huckabee. Lots of celebrities are behind Clinton and Giuliani, so when they come out with support for them, nobody bats an eye. Now, Huckabee's ad was infantile, but it's not going to help him win the nomination. Nobody's going to take him seriously after appearing onscreen with Chuck Norris cracking old jokes. Nobody who isn't already pulling for him is going to be inspired to learn more. Basically, what I'm trying to say is that the kind of person who will be swayed by celebrities voicing their opinions is not the same kind of person who will actually DO anything about it. If a candidate is at the top of the list anyway, odds are it's because they're smart enough to not make Chuck Norris jokes in a campaign ad.
To sum up: celebrities are likely going to use their clout to pust their political views. Some politicians, if they are desperate, will take advantage of this. This will likely not go exactly as planned because it will not give them enough edge to really enter the race and the people who care about celebrity testimonial aren't the people who will be affecting the election.
Lindsay's blog
By the way, what "deep, personal issues" do you have with Oprah? Did she run over your dog?