M Ted, I think the original post was not so much "you're all such racists" as "reports abroad say there's a large minority of Americans who are racist". Having said that, I personally haven't seen that kind of reporting. Whilst there may indeed be significant amounts of racism in the US, I don't know how far it goes. Interestingly, it might not actually make a large difference to the result - I think racism tends to be more common amongst lower-income people who are socially isolated, and they're less likely to be voting anyway.
I guess it's similar to my question about non-Christian candidates. The "Christian" bloc is such an important voting group that as PoppaGator says, there seems to be a strong need to create the impression of Christian faith even if you're not actually a believer. So maybe my question needed to be rephrased to ask whether the US is ready to accept a Prez who doesn't actively sell himself (or herself) as a Christian.
In the UK it's kind of the other way around - making a public show of your religion is a vote loser because it implies that people who don't worship your way are inferior, and Brits *hate* to be told how to think. So although Tony Blair is a very committed Christian, he kept that an extremely private matter throughout his stint as Prime Minister.