This article focuses on the legalization of same-sex marriages in Massachusetts and the impending battle between gay activists and social conservatives. Seldom in recent times has a clerical act inspired so much jubilation. One second past midnight on May 17th, gay marriage became legal in Massachusetts, and same-sex couples began to fill out marriage licence applications in Cambridge City Hall, specially opened for the occasion. War is an appropriate metaphor. Supporters, pointing out that May 17th was the 50th anniversary of Brown v Board of Education, claim the ceremonies in Massachusetts mark the biggest advance in civil rights since racial segregation was abolished. Conservatives, who see "the end of western civilisation" in the marriages, look back to 1973 and another Supreme Court ruling: Roe v Wade, which legalised abortion and started a culture war that has lasted for 30 years. Certainly, the full legalisation of gay marriage in Massachusetts took many liberal activists by surprise. Many assumed Vermont's civil unions (non-marriages with most of the legal advantages) would be the best they could get. The right's reaction was less militant than might have been expected. Yet the counterattack is only just around the corner and may precipitate years of conflict. Only a handful of liberal states, including Connecticut, Rhode Island and New York, have suggested they might honour same-sex marriages performed in Massachusetts.