Slate had a great piece on this; Dahlia Lithwick said it better than I can. Pay particular attention to the second paragraph:
Virginia voters go to the polls in the next few days to decide whether to amend their constitution not only to ban gay marriage, but also to refuse to recognize any legal arrangement between "unmarried individuals"—gay or straight—that confers marriagelike benefits. The ballot initiative is shocking not only in its bigotry against all unmarried couples, but in its attempt to transform a constitution—a document meant to lay out our highest freedoms and aspirations—into a vicious cudgel to separate "us" from "them."I'm a little confused as to why we need this change to the Virginia Constitution. I'm not alone.
The voters of Virginia have already made their feelings about gay marriage perfectly clear: State statutes already prohibit both civil unions and marriages between same-sex couples. Laws on the books already nullify marriages or civil unions entered into in any other state. So, having blocked any last road to Virginia recognizing a same-sex marriage, a civil union, or an out-of-state or Canadian gay marriage in Virginia, our cynical legislators have gone one step further: They propose doing away with adoption laws, custody arrangements, medical directives, or domestic-violence statutes with which both heterosexual and homosexual families protect their children and property.
Two months ago, Judge J. Harvie Wilkinson III, an esteemed Republican from the 4th Circuit Court of Appeals and beloved shortlister for the U.S. Supreme Court, wrote an almost unprecedented editorial for the Washington Post, urging Virginians to vote against Ballot Question 1. Nobody could accuse Wilkinson of being either a liberal activist or a reflexive supporter of gay marriage. His principal concern with the amendment is that, by constitutionalizing that which should merely be legislated, we enshrine in an ageless, timeless document, the passions of a fleeting legal moment. "The more passionate an issue, the less justification there often is for constitutionalizing it," he wrote. "Constitutions tempt those who are way too sure they are right."Intelligent people from all aspects of the political spectrum disagree with this change to the Constitution. Smart conservatives and progressives alike agree: Vote No on One.