Kerry's faith as pretense?

Duncan Frissell emailed me with a decidely more cynical view of Kerry's Catholic problem (see earlier posts), wondering whether Kerry actually is a "cynical nonbeliver." Over at the Technoptimist blog Duncan pursues this point further:

Kerry has said that, as an elected official, he must separate his personal religious views from his actions as a legislator and that it is not 'appropriate in the United States for a legislator to legislate personal religious beliefs for the rest of the country.'

But, I assume, it is OK for a communist legislator to legislate his personal communist beliefs for the rest of the country?

Why don't faithless Catholic politicians simply say that they are imposing their beliefs on us but that those beliefs are not the beliefs of their church; that (in fact) they don't share most of the beliefs of their church; and that they only maintain the pretense of faith for crass political advantage.

Duncan is undoubtedly correct that there's an element of crass political calculation in the religious posturing of Kerry -- as well as Bush, I submit -- but I'm hesitant to head down the road of second-guessing the sincerity of anyone's -- even a politician's -- professed faith commitment. (Goodness knows folks would have been justified in doing the same to me at various points in my life.) I'd rather take politicians at their word, and keep the debate to the consistency (or lack thereof) between their actions/policy positions and the core tenets of the particular faith tradition they claim.

Rob