There is much that is interesting here, including the commentary by Fr. Z. Lawler's chief point however seems to be this (Lawler's words):
"One way or another—because he is treated rudely, as an enemy; or because he is treated politely, as a foreign dignitary—Cardinal Dolan’s appearance in Charlotte will help Catholic voters to notice that they are no longer 'at home' in the Democratic Party. Like the cardinal they may be accepted as guests, but as long as the Democratic Party embraces the culture of Death, Catholic Democrats will be operating on alien territory. "Cardinal Dolan offered to attend the convention if his presence was wanted. The truth is that he is not wanted. But the Democratic Party has chosen to pretend, and that is a serious tactical error." [emphasis Fr. Z.'s]Fr. Z. asks: "Is Lawler on to something here?" I wish he were.