JFK never ran as a Catholic. JFK never intended to jam to his religion down America's throat. Romney, running as a religious right candidate, is doing quite the opposite. Romney isn't just running on his faith. He is openly proud of the fact that he plans to use his religion as a litmus test to determine his position on every issue. While JFK assured us that he wasn't going to be taking orders from the Pope, Romney assures us that he will be taking orders from Pat Robertson and the men at the Concerned Women for America.
Kennedy believed in the pluralism of America. Romney does not. Romney, like so many Republican candidates nowadays, wants you to live your life like a good member of HIS religion. And if you don't, he's going to pass laws making sure that you do.
That's why it's relevant that Romney is a Mormon. If we are expected to live under Mormon law, we deserve to know a bit more about that religion before casting our votes.
