Public support for gay marriage is at a record 53 percent, according to an ABC News/Washington Post poll released this month, the first time the poll has measured support for gay marriage above 50 percent. In 2004, support was 32 percent.

Among the young, the question appears settled: 68 percent of voters ages 18 to 29 support same-sex marriage rights.

The findings reflect broad trends revealed in other polls. As support has steadily risen, "gay marriage has lost its clout [to divide voters] as a wedge issue,'' said Darrell West, vice president and director of governance studies for the Brookings Institution, a Washington think tank. "Same-sex marriage has become mainstream.''