I was rebutting the notion that Catholics were so monolithically Catholic. Incidentally, Dennis Kucinich and Mark Foley are not Catholic, merely of Catholic extraction. Both have very publicly renounced their Catholicism, which is quite an extraordinary act for a politician.
I would also add that many state Democratic organizations nominate nominal Catholics precisely because the religious affiliation helps their candidates seem more moral (for instance, Landrieu, Durbin, Casey, Biden, Mikulski, and Kerry.)
Catholics are no more Democratic than Protestants; it's just that for political polling, only those Protestants who are active in their churches mention their denomination. Catholics are more Democratic than White Protestants, but this is more an issue of class and geography than of denomination. Even White Protestants, when from the states Catholics are from, tend to be more Democratic then Catholics, which certainly is surprising given that Catholics come from Democratic tradition (from before Roe v. Wade, and the Homosexual Revolution); Catholics have been shifting rightward while Protestants have been shifting leftward.
..but even still, the best measure of liberalism is still the lack of religious adherence, not denomination.