I keep getting emails asserting that Kerry's mentioning of Mary Cheney is somehow offensive or gratuitous or a "low blow". Huh? Mary Cheney is out of the closet and a member, with her partner, of the vice-president's family. That's a public fact. No one's privacy is being invaded by mentioning this. When Kerry cites Bush's wife or daughters, no one says it's a "low blow." The double standards are entirely a function of people's lingering prejudice against gay people. And by mentioning it, Kerry showed something important. This issue is not an abstract one. It's a concrete, human and real one. It affects many families, and Bush has decided to use this cynically as a divisive weapon in an election campaign. He deserves to be held to account for this - and how much more effective than showing a real person whose relationship and dignity he has attacked and minimized? Does this makes Bush's base uncomfortable? Well, good. It's about time they were made uncomfortable in their acquiescence to discrimination. Does it make Bush uncomfortable? Even better. His decision to bar gay couples from having any protections for their relationships in the constitution is not just a direct attack on the family member of the vice-president. It's an attack on all families with gay members - and on the family as an institution. That's a central issue in this campaign, a key indictment of Bush's record and more than relevant to any debate. For four years, this president has tried to make gay people invisible, to avoid any mention of us, to pretend we don't exist. Well, we do. Right in front of him.