In an interview Thursday, Edwards told the St. Louis Post-Dispatch: "We're both opposed to gay marriage and believe that states should be allowed to decide this question,"

On Tuesday, Missouri became the first state since the legalization of same-sex marriage in Massachusetts to vote on amending its constitution to prevent such unions. More than 70 percent of voters supported the amendment.

Adopting a states' rights approach, Kerry and Edwards have opposed the administration's efforts to amend the U.S. Constitution to stop gays from marrying. Yet by supporting only limited rights such as civil unions and not objecting to state amendments like the Missouri ban, the Democratic candidates have disappointed many gay rights activists.

"Kerry-Edwards is better than Bush-Cheney on human rights, but it is frustrating that both major candidates oppose full equality," said Geoffrey Kors, executive director of Equality California.

"Whether we have Bush-Cheney, who support amending the federal Constitution, or Kerry-Edwards, who don't object to amending state constitutions, the GLBT community is going to have to become more assertive in demanding our rights from our elected officials," Kors said, adding that Equality California has yet to endorse a ticket for president.

Other GLBT groups took a sanguine response to Edwards' remarks.

"The Kerry-Edwards ticket has the strongest human rights record of any ticket in history, and we in the LBGT community have to keep our eye on the prize: defeating George Bush," said Steven Fisher, communications director for Human Rights Campaign.

Instead of denouncing the Kerry-Edwards stance, Fisher assailed Republicans for pushing the gay marriage issue so hard in an election year.

"We think the American people will see these state ballot efforts as George Bush's attempt to divide the American people and distract them from the failures of his administration."

A July 30 Zogby poll showed the presidential race in Missouri to be a statistical dead heat in this key swing state.

Louisiana residents are to vote on a marriage amendment Sept. 18. Then Arkansas, Georgia, Kentucky, Mississippi, Montana, Oklahoma, Oregon and Utah are to vote on the issue Nov. 2. There also are initiatives pending in Michigan, North Dakota and Ohio.

Four states -- Alaska, Hawaii, Nebraska and Nevada -- already have similar amendments in their constitutions.