A battle over a federal law that defines marriage as a union between a man and a woman appears headed for the Supreme Court after an appeals court ruled Thursday that denying benefits to married gay couples is unconstitutional. In a unanimous decision, the three-judge panel of the 1st U.S. Circuit Court of Appeals in Boston said the 1996 law deprives gay couples of the rights and privileges granted to heterosexual couples. The court didn't rule on the law's more politically combustible provision — that states without same-sex marriage cannot be forced to recognize gay unions performed in states where...