The politics of the marriage amendment. PRESIDENT BUSH'S endorsement last week of a constitutional amendment preserving the current understanding of marriage, and the decision of John Kerry and other leading Democrats vehemently to oppose it, ensures that the marriage debate will be front and center in American politics. And it will be prominent not just in 2004, but very likely for a number of election cycles to come. Until recently, that seemed far from certain. One year ago, gay marriage looked too radical to enter mainstream debate as early as 2004. One week ago, with the photogenic mayor of San...