President Barack Obama has hailed as "a victory for America" the U.S. Supreme Court ruling Friday that same-sex couples have the right to marry anywhere in the United States.
In a five to four decision, the high court declared that the U.S. Constitution's guarantees of due process and equal protection for all overrule any state's attempt to outlaw same-sex marriages.
Previously only 36 of the 50 states plus the District of Columbia had allowed gay marriage.
Gay marriage supporters broke out in cheers as word of the decision spread over a crowd of hundreds who had gathered outside the court building.
"This decision will end the uncertainty hundreds of thousands of same-sex couples face. It will strengthen all of our communities," Obama said at the White House after the historic ruling.
"Progress often comes in small increments, sometimes two steps forward, one step back," he continued. "Sometimes, there are days like this – when that slow, steady effort is rewarded with justice that arrives like a thunderbolt."
"America should be very proud," Obama said.
WATCH: Related video of President Barack Obama
Obama telephoned the lead plaintiff in the case, Jim Obergefell, congratulating him on live television.
In 2013, Obergefell sued the state of Ohio over its refuals to list him as the surviving spouse on the death certificate John Arthur, the man Obergefell married in Maryland where same-sex marriage is legal.
WATCH: Jim Obergefell reacts to Supreme Court Ruling
Since Ohio banned same-sex marriage in the state, the state did not recognize the Obergefell's marriage to Arthur.
"America has taken one more step toward the promise of equality enshrined in our Constitution, and I'm humbled to be part of that," Obergefell said after the ruling.
Obergefell spoke to reporters outside the court. “Today’s ruling from the Supreme Court affirms what millions across this country already know to be true in our hearts, our love is equal and that the four words etched above the Supreme Court, “Equal Justice Under Law”, apply to us too.”
Tony Perkins, president of the Family Research Council, said on Twitter the ruling was a “shocking abuse of power, and will never be accepted.”
Speaker of the House John Boehner issued a statement, saying he was "disappointed that the Supreme Court disregarded the democratically enacted will of millions of Americans by forcing states to redefine the institution of marriage."
Boehner's statement also said that "marriage is a sacred vow between one man and one woman, and I believe Americans should be able to live and work according to their beliefs."
Representative Nancy Pelosi, leader of Democrats in the House, called the Supreme Court's ruling on gay marriage a “transformative” decision, saying the ruling “unequivocally affirmed that equal justice under the law means marriage equality” for gay, lesbian, bi-sexual and transgender Americans.
“This decision is about creating a future where loving, committed families are able to live with dignity. This is about freedom. This is about love,” she said.
Justice Kennedy Writes for the Majority
Justice Anthony Kennedy wrote the majority decision just as he did in three previous gay rights cases before the court dating back to 1996. Kennedy wrote that gays and lesbian couples asked for “equal dignity in the eyes of the law.” He added, “The Constitution grants them that right.
Conservative Justice Antonin Scalia was among the four dissenters. He wrote the decision shows the court is “a threat to American democracy.”
Conservatives Vow to Fight On
Gay marriage opponents were also out in force in front of the court including Jennifer Marshall with the conservative Heritage Foundation. Marshall said the battle over gay marriage will continue.
“Well this is a disappointment because the court should have respected the fact that nothing in the Constitution required the re-definition of marriage. Marriage policy has historically been and should remain under the authority of states and the American people. The court has issued a decision but it will not end the conversation about what marriage is any more than the Roe versus Wade decision has ended the abortion debate.”
The outcome is the culmination of two decades of Supreme Court litigation over marriage, and gay rights generally.
The ruling is the Supreme Court's most important expansion of marriage rights in the United States since its landmark 1967 ruling in the case Loving v. Virginia that struck down state laws barring interracial marriages.
Public Opinion Shift
Public opinion has shifted strongly in support of gay marriage in recent years, said analyst Karlyn Bowman of the American Enterprise Institute.
“American’s views about gay marriage have changed remarkably fast in terms of being more accepting of gay marriage overall," Bowman said.
"And it has been one of the most rapid transformations I’ve seen in public opinion, in part because so many know someone who is gay or have a friend who is gay or a family member who is gay and that kind of proximity has actually created greater acceptance," he added.
Georgetown University law professor Nan Hunter told VOA’s Mike Bowman outside the court that Friday’s decision reflected that shift in public opinion. “I’m not sure America changed today. I think the court today said we see how America has changed.”
VOA's Michael Bowman contributed to this report.