UPDATE 1-Supreme Court gay marriage decision helps U.S. immigration bill
* Citizens now allowed to sponsor same-sex spouse for green card
* In light of Supreme Court decision, Leahy will not push same-sex amendment
(Adds comment From human rights group)
WASHINGTON, June 26 (Reuters) - Senators who wanted a gay rights provision added to the sweeping U.S. immigration reform bill backed off on Wednesday after the Supreme Court struck down a key part of the federal law that defined marriage as between a man and a woman.
The decision removes one of the last obstacles for the Senate to pass the legislation that would overhaul the country's immigration system and give millions of illegal immigrants a chance to earn citizenship over 13 years.
Senate Democrats had been under pressure to include a provision in the bill allowing citizens to petition for their foreign-born, same-sex spouses to immigrate to the United States.
That privilege had been blocked by the Defense of Marriage Act, which said that for federal government purposes, marriage was between a man and a woman. On a 5-4 decision on Wednesday, the court struck down parts of the act.
Now, legally married gay men and women will be entitled to claim federal benefits that are available to heterosexual married couples, including the ability to sponsor a foreign-born spouse for permanent residency, or a "green card."
"With the Supreme Court's decision today, it appears that the anti-discrimination principle that I have long advocated will apply to our immigration laws and binational couples and their families can now be united under the law," said Democrat Patrick Leahy, the chairman of the Senate Judiciary Committee.
When Leahy's committee was working on the legislation in May, he was forced to withdraw his gay rights proposal after Republican senators threatened to reject the entire bill if the same-sex amendment was added.
Democratic Senators Charles Schumer and Richard Durbin, two of the bill's original authors, and the rest of Leahy's fellow Democrats on the committee also said they could not support the provision if it killed the bill.
On Wednesday, Leahy said: "As a result of this welcome decision, I will not be seeking a floor vote on my amendment."
It was not clear Democratic leaders would have allowed the full Senate to vote on Leahy's provision - a vote that would have been difficult when most Democratic lawmakers and a handful of Republican senators have voiced support for gay marriage.
Rather, Democratic leaders gambled that the Defense of Marriage Act would get struck down and solve the problem.
"That gamble paid off," said Fred Sainz, a spokesman for gay rights group Human Rights Campaign.
"It remains a deeply painful moment for us because we wished that our allies stood up for us. But at the end of the day, the end result is the same and (Schumer and other Democratic Senators) have been staunch allies of gay equality," he said.
The Senate is expected to vote on the final bill on Friday. The legislation would also set aside $46 billion to strengthen security at the U.S.-Mexico border and create new work visas for farm aides, unskilled laborers and the tech industry.
Before Wednesday, 12 U.S. states plus the District of Columbia allowed same-sex couples to marry. Homeland Security Secretary Janet Napolitano said her department will be working to implement the high court's decision so that all married couples will be treated equally and fairly.
"At long last, we can now tell our families that yes, they are eligible to apply for green cards," said Rachel Tiven, executive director of gay rights group Immigration Equality.
The House of Representatives has yet to take up an immigration reform bill, and Republicans who control the House have voiced deep skepticism over the Senate plan.
(Additional reporting by Thomas Ferraro; Editing by Fred Barbash, Vicki Allen and Bernard Orr)