Today, marriage licenses will be issued in all 50 states and the District of Columbia.
It will be the first time that couples in a state will be able to legally wed, after a decade of litigation.
It will also mark a significant milestone for couples who have had a legal fight over the issue.
The Marriage Equality Act was introduced in the Senate by Democrat Chuck Schumer, and the House of Representatives unanimously approved it by a vote of 217-213.
It now heads to President Donald Trump’s desk for his signature.
Trump signed the bill into law on Jan. 1.
“Today marks a major milestone in the history of marriage, one that will benefit millions of Americans who want to be able and willing to wed legally,” Schumer said in a statement.
“We can’t let this issue go unchallenged, and I hope the president will take the time to review the bill and take the necessary steps to ensure that it will not be repealed by the next president.”
The law, which has been hailed by civil rights groups as the first step to equal rights for same-sex couples, came after decades of court battles that pitted religious groups, business groups, and state and local governments against the federal government.
In December, a federal judge in Kentucky struck down the federal ban on same-day marriage, ruling that the state’s ban violated the equal protection clause of the 14th Amendment.
The Supreme Court, which had refused to hear the case, then issued an order requiring Kentucky to comply with federal law.
But in December, the U.S. Court of Appeals for the 4th Circuit issued a stay on the stay, saying that it was necessary because the stay would affect marriages already in the state.
The court later ordered Kentucky to allow same-semester weddings to resume, but not to extend the stay.
Last month, the Supreme Court allowed the U-S government to continue to deny federal benefits to same-gender couples.
That ruling was not challenged by same-same-sex marriage supporters, who say that the government has no legitimate authority to deny benefits to couples.
Supreme Court Justice Anthony Kennedy, who was nominated by President Bill Clinton, joined the court’s decision.
He wrote that the “government’s interest in preserving its own status quo is a legitimate one, which we cannot allow to stand.”
He also said that the plaintiffs who brought the case are entitled to “equal protection” under the law.
The state of Kentucky and Kentucky officials said that their legal battles over marriage equality are not over.
They argue that they were wrong to oppose same-date marriages before the Supreme, and that the courts should not rewrite the law as a result.
“I am convinced that the Supreme will ultimately rule in the government’s favor,” Kentucky Attorney General Andy Beshear said in December.
“This decision is a setback for discrimination in the eyes of the law and is a clear reaffirmation of the government government’s constitutional authority to define marriage as a union between one man and one woman.”
In December 2016, Kentucky Attorney Generals office announced that it would not defend the federal marriage ban, which was challenged by the U.-S government.
A month later, the United States Supreme Court declined to hear an appeal of the ruling by the Kentucky Attorney Gen. office.
A number of states have issued similar marriage licenses to same sex couples.