NEW YORK (Reuters) - Half of Americans believe same-sex couples should have the same right to wed as heterosexuals do, slightly down from a year ago but marking the second year that a majority of Americans have supported same-sex marriage, according to a Gallup Poll survey released on Tuesday.
The poll comes as North Carolina voters go to the polls on Tuesday to vote on a constitutional amendment that would define marriage as a union between a man and a woman, and effectively ban same-sex marriage and civil unions.
President Barack Obama, who has stopped short of supporting same-sex marriage but has described his position on the issue as evolving, faces mounting pressure to change his stance, especially as his top aides come out in favor of legalization.
Over the weekend, Vice President Joe Biden said he is "absolutely comfortable" with same-sex marriage, and Education Secretary Arne Duncan later said publicly that gay marriage should be legal.
Six states, plus the District of Columbia, have extended marriage rights to gay couples. Twenty-eight states ban such marriages.
Gallup's survey a year ago marked the first time in the poll's history that a majority of Americans - 53 percent - said they favored legalization of same-sex marriage. Gallup first asked the question in 1996, when only 27 percent of respondents supported it.
This year's poll found Americans divided along political and religious lines.
Nearly two-thirds of Democrats support allowing same-sex marriage, along with more than half of independents, while fewer than a quarter of Republicans believe it should be allowed.
Among Americans with "no religious identify," the overwhelming majority backs allowing same-sex marriage, along with just over half of Catholics. Nearly six in ten Protestants oppose legalization.
Other recent surveys have also found the country is split over whether to extend marriage rights, with younger and less religious people tending to be more supportive of marriage equality.
In a survey released last month, the Pew Research Center found 47 percent of people favored same-sex marriage while 43 percent opposed legal marriages by gay and lesbian couples. In 2008, 39 percent favored gay marriage and 51 percent opposed it.
(Reporting By Edith Honan; Editing by Paul Simao)