I would say that Kerry already has lost the support of "those Catholics who really take their Catholicism seriously." His "Catholic" supporters are more the cafeteria Catholics who want to pick and choose. As for the analogy, in my opinion it wasn't strong enough simply because I don't think the Jewish faith considers violation of kosher requirements to be murder (I have only the very vaguest idea of the theological basis for the dietary requirements so I hope I'm not misstating anything here). There are also, I believe, several branches of Judaism with varying requirements. I just don't think the analogy goes far enough. The key point is that the Catholic church considers abortion to be murder. To understand the Catholic position, just substitute "murder" for "abortion" in any argument, i.e., "I don't condone murder, but I am not going to impose my views on anyone else," "the legal question has been settled that women have a right to murder"... etc. I believe that part of the problem is an idea that opposition to abortion is based on some complex point of Catholic theology (like kosher diet is to a non-Jewish person-- it's difficult to understand if you haven't studied it). The Catholic church's opposition to abortion is based on its opposition to murder. When Kerry supports abortion, he supports murder. You don't get to do that just because you were an altar boy or because you carried a rosary in Vietnam.
This reply is to everyone here! I take a similar position to Kerry on first trimester abortion (though I support a ban on late-term abortion and support parental notifications and waiting periods, unlike Kerry); I am also a practicing Catholic. First of all, for anyone to make the claim that one cannot be pro-choice and Catholic is to make a claim that the Pope himself would not make (and has not!). Clearly, the Church believes itself to be correct on this issue, and affirms its position as objectively true. Nonetheless, there is no precedent in Canon Law for denying Communion to someone on the basis of dissenting from the Church on abortion *and of course, I assume that everyone here affirms the Church's teaching on the death penalty.* It is true that having an abortion carries the penalty of automatic excommunication; but Catholics are free to personally dissent from the Church's teaching on this issue. When non-Catholics convert, they are not asked to accept the Church's position on abortion as infallible; they are asked only to affirm the fundamentals of the faith found in the Creed, and renounce the works of Satan. Conservative Catholics may affirm that abortion is a work of Satan--and that may be true--but nowhere does the Church teach that this is specifically understood to be included in that renunciation. My biggest problem with John Kerry--and most pro-choice Catholics--is that they are actually pro-abortion. I think first-trimester abortion should be legal, because I do not believe it is a person until viability, though it is clearly a life, in the biological sense. However, I work to support programs that promote abortion alternatives--because I genuinely want to see abortion rare. The question I wish more Catholics would be asking is--okay, so you say want abortion to be rare (as Clinton said, "safe, legal, and rare")--what are you doing to try and help make it less common?!