For conservative activists, the Defense of Marriage Act is the levee holding back the flood. The 2003 Supreme Court decision that threw out a Texas sodomy law sparked scores of civil challenges to state and federal gay-marriage restrictions based on discrimination and other claims. Conservative legal organizations have mobilized in opposition to these lawsuits and to increasing activity on the issue in state legislatures. One priority is to establish the right not to recognize same-sex marriage on religious grounds. In New Hampshire, Gov. John Lynch (D) is seeking protections for churches and their employees before he signs his state’s pending same-sex marriage bill into law.

“This is kind of like the abortion debate 30 years ago. Some states changed their laws; some didn’t,” said Jordan Lorence, senior counsel for the conservative Alliance Defense Fund, who counseled New Hampshire Republicans on the religious exclusion, and whose group is active in other state and federal cases.

“Does the Supreme Court come in with a Roe v. Wade trump card?” Lorence asked. “How this is all going to play out over time, I think the new Supreme Court nominee is going to be a factor . . . which makes it a legitimate area of questioning.”