Support for gay marriage reached a new high in the latest ABC News/Washington Post poll, marking a dramatic change in public attitudes on the subject across the past decade. Fifty-eight percent of Americans now say it should be legal for gay and lesbian couples to wed. That number has grown sharply in ABC News/Washington Post polls, from a low of 32 percent in a 2004 survey of registered voters, advancing to a narrow majority for the first time only two years ago, and now up again to a significant majority for the first time. Most Americans, moreover, say the U.S....