Vice President Joe Biden said the repeal of "don't ask, don't tell" in the military will help pave the way for a consensus on same-sex marriages throughout the country.
In an interview on ABC's Good Morning America, aired on Christmas Eve, Biden said he agreed with President Obama that the nation's attitude toward gay unions is "evolving."
"I think there is an inevitability for a national consensus on gay marriage," Biden said.
The vice president also mentioned the 1996 Defense of Marriage Act, which defines marriage as between a man and a woman, a law Obama has repeatedly said should be repealed.
"I think you're going to see, you know, the next effort is probably going to be to deal with so-called DOMA [Defense of Marriage Act]," Biden predicted.
Obama recently said he believes same-sex couples should have the same legal rights that married couples enjoy. Now that gays in the military will be able to serve openly, the president said he is still thinking about gay marriages.
During his 2008 campaign, Obama vowed to be more supportive of homosexual rights generally. But gay rights groups have not been satisfied with his follow through during the first two years of his administration.
In October, the Justice Department repealed decisions by a Massachusetts judge who called the law unconstitutional for denying federal benefits to married gay couples.
In July, U.S. District Judge Joseph Tauro ruled that DOMA is unconstitutional because it interferes with a state's right to define marriage and denies an array of federal benefits to homosexual couples, including the ability to file joint tax returns.
AP contributed to this report.