Feb. 1, 2011 -- Barbara Bush, the daughter of former President George W. Bush, has joined her mother and a growing number of former administration officials in publicly expressing support for same-sex marriage.

Bush, who has never commented publicly on the issue, appears in a new online PSA video for the Human Rights Campaign, a gay rights group.

"I'm Barbara Bush and I'm a New Yorker for marriage equality," she says. "New York is about fairness and equality and everyone should have the right to marry the person that they love. Join us."

The video, part of a series featuring high-profile New Yorkers, comes as rights advocates make a renewed push to legalize same-sex marriage in the Empire State, after the legislature blocked such a step in December 2009.

Bush has also added herself to a growing list of high-profile conservatives with ties to the Bush administration who have recently spoken out in favor of extending marriage rights to gays and lesbians.

Former Vice President Dick Cheney, former first lady Laura Bush, former Solicitor General Ted Olson and 2004 Bush campaign manager and former Republican National Committee Chairman Ken Mehlman all support same-sex marriage.

Their views -- and advocacy on the issue -- are significant given that opposition to gay marriage and a constitutional amendment banning it were key elements of Bush's 2004 reelection campaign.

"When couples are committed to each other and love each other, that they ought to have, I think, the same sort of rights that everyone has," Laura Bush told CNN's Larry King last year, adding that she and her husband disagree on the issue.

"I understand totally what George thinks and what other people think about marriage being between a man and a woman. And it's a real ... reversal really for [them] to accept gay marriage," she said.

Cheney, who has a gay daughter, said in 2009 that "people ought to be free to enter into any kind of union they wish. Any kind of arrangement they wish."

Mehlman, who is gay, works as a fundraiser and strategist for the American Foundation for Equal Rights -- a group that supports same-sex marriage and is suing to overturn California's Proposition 8 -- while Olson is one of the lead attorneys in the case.

Obama Views Might Be Changing

Other prominent Republicans, including Cindy and Meghan McCain, have also campaigned for gay marriage across the United States.

Whether the high-profile support for gay marriage will trigger a broader shift within the GOP is far from certain. The party's official 2008 platform still calls for a constitutional amendment to define marriage between a man and a woman.

In New York, where the video campaign featuring Barbara Bush is focused, a clear majority -- 56 percent -- support marriage rights for same-sex couples, according to a Quinnipiac University poll released last week.

But nationwide, the most recent ABC News-Washington Post poll showed a narrow divide on legalization of gay marriage, with 47 percent in favor and roughly 50 percent opposed.

President Obama, who has opposed extending marriage rights to gays and lesbians, recently signaled that his views might be changing.

"My feelings are constantly evolving," Obama told reporters in December about his position on gay marriage. "I have friends, I have people who work for me, who are in powerful long-lasting gay or lesbians unions.

"My baseline is a strong civil union that affords them legal protections," he said. "I recognize from their perspective, it's not enough."

Illinois became the sixth state Monday to legalize civil unions or domestic partnerships for same-sex couples, which carry many of the same legal rights as marriage. Five states and the District of Columbia allow same-sex marriage.