Bill Safire explains that Kerry used the fact of the Cheney daughter’s lesbianism was "part of a deliberate Kerry campaign strategy." The campaign thought it was a no-lose proposition. "One purpose was to drive a wedge between the Republican running mates. President Bush supports a constitutional amendment limiting marriage to a union of a man and a woman; Cheney has long been on record favoring state option, but always adds that the president sets administration policy. That rare divergence of views is hardly embarrassing.
The sleazier purpose of the Kerry-Edwards spotlight on Mary Cheney is to confuse and dismay Bush supporters who believe that same-sex marriage is wrong, to suggest that Bush is as soft on same-sex as Kerry is, and thereby to reduce a Bush core constituency’s eagerness to go to the polls."