Former President Barack Obama and his wife Michelle offered their condolences to Edith Windsor, the plaintiff in the U.S. Supreme Court case that struck down the Defense of Marriage Act in 2013, who died Tuesday at the age of 88.

In a statement from his office, Obama said he spoke to Windsor several days ago and told her how much of a difference she had made in the U.S.

"In my second inaugural address, I said that if we are truly created equal, then surely the love we commit to one another must be equal as well," Obama said. "And because people like Edie stood up, my administration stopped defending the so-called Defense of Marriage Act in the courts. The day that the Supreme Court issued its 2013 ruling in United States v. Windsor was a great day for Edie, and a great day for America -- a victory for human decency, equality, freedom, and justice. And I called Edie that day to congratulate her."

"Two years later, to the day, we took another step forward on our journey as the Supreme Court recognized a Constitutional guarantee of marriage equality," he added. "It was a victory for families, and for the principle that all of us should be treated equally, regardless of who we are or who we love."

Obama did not support same-sex marriage when he first ran for president, although he had expressed support for LGBT rights. He publicly endorsed same-sex marriage in 2012 after receiving pressure from Democrats and LGBT advocates.

Striking down DOMA permitted same-sex couples the same federal benefits as heterosexual couples.

Windsor is remembered as a fighter for LGBT rights because the Supreme Court ruling in her case led to the Obergefell v. Hodges ruling, which legalized same-sex couples to marry across the U.S.