Offer them a deal they can't refuse: Total abortion rights, with the possible exception of practices such as partial birth abortions which could rightly be construed as infantacide, for total gun rights, i.e. the elimination of every law in the land involving firearms other than the 2'nd ammendment.
Take those two poisonous issues straight out of American politics in a single move. The dems don't have any other real issue besides abortion rights; they'd be history along with the whigs and tories in five years.