Former U.S. Attorney General Ted Olson, the conservative lawyer who argued for Bush’s recount, has died

Former U.S. Attorney General Ted Olson, who served two Republican presidents as one of the country’s best-known conservative lawyers and successfully advocated for same-sex marriage, has died.

WASHINGTON (AP) — Former U.S. Attorney General Ted Olson, who served two Republican presidents as one of the nation’s best-known conservative lawyers and successfully argued on behalf gay marriagedied on Wednesday.

The law firm Gibson Dunn, where Olson had worked since 1965, announced his death on its website. No cause of death was given.

Olson has been at the center of some of the biggest lawsuits in recent decades, including the victory on behalf of George W. Bush in the 2000 presidential election recount in Florida, which went before the U.S. Supreme Court.

Bush appointed Olson as his attorney general, a position the attorney held from 2001 to 2004. Olson had previously served at the Justice Department as an assistant attorney general during President Ronald Reagan’s first term in the early 1980s.

According to Gibson Dunn, Olson has argued 65 cases before the Supreme Court during his career.

One of Olson’s most prominent cases put him at odds with many fellow conservatives. After California passed a ban on same-sex marriage in 2008, Olson joined forces with former opponent David Boies, who had represented Democrat Al Gore in the presidential election, to represent California couples seeking the right to marry.

A federal judge in California ruled in 2010 that the state’s ban violated the U.S. Constitution. The US Supreme Court upheld that decision in 2013.

“This is the most important thing I’ve ever done, as a lawyer or as a person,” Olson later said in a documentary about the marriage case.

He told The Associated Press in 2014 that the marriage case was important because it involves “tens of thousands of people in California, but really millions of people in the United States and around the world.”

Barbara Becker, managing partner of Gibson Dunn, called Olson “creative, principled and fearless.”

“Ted was a titan of the legal profession and one of the most extraordinary and eloquent advocates of our time,” Becker said in a statement.