Frankly, when I was watching the third debate, and Kerry brought up Mary Cheney, I was instinctually struck with what a creepy move it seemed to be. When Edwards did it in the VP debate, it was in context--it was the subtext of the moderator's question. That said, even there, I found the move not particularly kosher, since the moderator's question was phrased in such a way as to make the underlying facts obscure to those who don't follow these things closely. But with Kerry, there really was no excuse. Out of the total pool of all openly gay people in the world, Kerry decided to make his point by drawing attention to Mary Cheney. I quite honestly believe Kerry did this in order to turn off culturally conservative voters from voting for Bush-Cheney, while still being able to claim to support gay rights, in exactly the way that Phil observes below.
This is a case where I think the honorable strategy would have been to be more explicit rather than less. An honorable use of Mary Cheney would have been the following:
"The daughter of my opponent's running mate is gay, out and unashamed of her identity. My opponent's running mate, whom he claims to depend upon for advice and counsel, doesn't agree with his position on the need for a gay marriage amendment. He does so, presumably, for the perfectly sound reason that he thinks that, if we want to treat homosexuals as equal citizens, it makes more sense to give them an opportunity, at least in states where they can convince their fellow citizens, to live in the bounds of marriage rather than to be forced to live without such a support, which any honest straight person would admit is a powerful support for fidelity and commitment. So my question, President Bush, is why, if you can't even convince your own vice-president of the need for a gay marriage amendment, you believe so strongly in amending the constitution to outlaw allowing people like Mary Cheney to marry in states that are happy to let them do so?"
In this case, the use of Mary Cheney would be designed for the reasonable purpose of heightening the differences between the president and VP. Notice however, that even in this formulation, you could do most of the work without having to raise her at all. This convinces me that Kerry is engaged in a scummy, sleazy, dishonorable effort to take advantage of a prejudice he claims to deplore. He should be ashamed.