The Supreme Court is set to confront the issue of gay marriage for the first time in 40 years in two cases set for argument in late March. Same-sex couples are asking the justices to strike down California's Proposition 8, which banned gay marriage in the state just six months after a court ruled that preventing gays and lesbians from marrying was unconstitutional. In a second case, a New York City widow is urging the court to strike down the federal Defense of Marriage Act (DOMA), which limits federal benefits for same-sex couples. Edith Windsor had to pay a $363,000 federal tax bill on her late wife's estate that would not have been levied on an opposite-sex spouse. The Obama administration says both laws are unconstitutional. House Republicans stepped into the Windsor case to defend DOMA. Court watchers say the justices are likely to be closely divided along conservative-liberal lines, with Justice Anthony M. Kennedy widely seen as having the pivotal vote on the nine-member bench.

Kenneth Jost is Supreme Court editor, CQ Press; associate editor, CQ Researcher; and author of The Supreme Court Yearbook since the 1992-1993 edition.