Senate Majority Leader Harry Reid. (Photo: AP)

Reid, who voted in 1996 for the Defense of Marriage Act — which defined marriage as between a woman and a man — but opposed a 2008 effort to amend the constitution to that effect, said in a statement that his “personal belief is that marriage is between a man and a woman” and that the issue should be left to the states.

But, he added, “in a civil society, I believe that people should be able to marry whomever they want, and it’s no business of mine if two men or two women want to get married. The idea that allowing two loving, committed people to marry would have any impact on my life, or on my family’s life, always struck me as absurd.”

And he said conversations with his children and grandchildren have persuaded him that marriage equality “will carry the future.”

A Mormon, Reid has long said he agreed with his church’s position against gay marriage. But he has also supported gay rights, including repealing the military’s “Don’t Ask, Don’t Tell” policy.

Reid’s statement came late in the day, hours after Obama told ABC News that he believes same-sex couples should be allowed to marry, reflecting what he had termed his personal evolution on the issue.

Reid’s comments highlighted the tricky situation that Obama’s shift has created for Democrats who had previously voiced opposition to gay marriage.

Reid’s statement was only part of an avalanche of reaction from Capitol Hill, which largely broke along partisan lines.

House Speaker John A. Boehner (R-Ohio) told Fox Business Network Wednesday that “I’ve always believed that marriage was between a man and a woman. The Republicans here on Capitol Here are focused in on the economy. The American people are still asking ‘Where are the jobs?’ and our focus is going continue to be on the economy like it has been for the last year and a half.”

When told of Obama’s comments, Sen. Marco Rubio (R-Fla.) asked “So he now agrees with his vice president?”

“I agree with the old Barack Obama,” Rubio said.

Democrats warmly supported the president’s new position.

House Minority Leader Nancy Pelosi (D-Calif.) said the president’s statement “marks progress for the civil rights of LGBT Americans and all Americans,” and added later that “Republicans are standing on the wrong side of history.”

Rep. Jared Polis (D-Colo.), who in 2008 became the first openly gay man to run for Congress and win, called Obama’s announcement “welcome news for American families” and said he looked forward to working with the president “to strengthen the institution of marriage by securing the right of all Americans to marry the person they love.”

Sen. Barbara Boxer (D-Calif.), whose state has served as a flashpoint in the gay marriage debate, said the president’s remarks have “nothing to do with politics and it has everything to do with equality.”

Boxer said she had believed Obama when he said that his position was “evolving” on gay marriage, because she herself once only backed permitting domestic partnerships, until the California Supreme Court ruled in 2006 that the gay marriage issue should be settled by referendum.

“That was my timetable, that was my home state,” Boxer said. “That’s how I evolved. Vice President Biden evolved on his timetable, and President Obama evolved on his timetable.”

Rep. Barney Frank (D-Mass.), who acknowledged being gay while serving in Congress, and will marry his partner in a Massachusetts ceremony in July, said he hoped the president’s support might give a boost to gay marriage supporters in Maryland. They are hoping their state will approve same-sex marriage at the ballot box in November.