Right to Privacy
Problematically, however, a right to privacy is not explicitly mentioned in the Constitution. The majority in Griswold held that it was among the unenumerated rights implied by the Constitution's "penumbras" (which sound like something a sodomy law might keep you away from). The Griswold case didn't settle the matter, and the right to privacy quickly became the Tinkerbell of constitutional rights: clap your hands if you believe.
Liberals clap. We love the right to privacy because we believe adults should have access to birth control, abortion services and pornography as well as the right to engage in gay sex. Social conservatives hate the right to privacy for the very same reason, as they seek to regulate private behaviors from access to birth control to masturbation. (Think I'm kidding about masturbation? In Justice Antonin Scalia's dissent in Lawrence v. Texas, he wrote that the majority's decision called into question the legality of state laws against "masturbation, adultery, fornication.")
If the Republicans can propose a constitutional amendment banning gay marriage, why can't the Democrats propose a right to privacy amendment? Making this implicit right explicit would forever end the debate about whether there is a right to privacy. And the debate over the bill would force Republicans who opposed it to explain why they don't think Americans deserve a right to privacy - which would alienate not only moderates, but also those libertarian, small-government conservatives who survive only in isolated pockets on the Eastern Seaboard and the American West.
If done correctly it could be an elegant way of attacking conservative ideology. Sweet.