Attorney Ted Olson, a partner at Gibson Dunn & Crutcher. (Jeffrey MacMillan/Capital Business)

For renowned Washington attorney Ted Olson, mounting the legal battle against Proposition 8, the California initiative banning same-sex marriage, doesn’t just mark a high point in his 45-year career — during which he has argued nearly 60 times before the Supreme Court, and cemented George W. Bush’s victory in the 2000 presidential election.

“This has been the highlight of my life,” Olson said last week at the annual networking dinner hosted by Gibson Dunn & Crutcher for Georgetown Law’s LGBT student group, Outlaw. “This is the most important thing we’ve done in our lives. It’s not just become a legal challenge, but it’s about the hearts and minds of a country changing.”

The dinner and panel discussion, held at the law firm’s downtown office, drew more than 60 attorneys and law students including Georgetown University Law Dean William Treanor and Marriott vice president and assistant general counsel Ward Cooper.

Olson, lead co-counsel for the plaintiffs challenging Prop. 8, joined two other Washington partners, Matthew McGill and Amir Tayrani, in recounting the emotional 12-day trial in San Francisco federal court that culminated in Judge Vaughn Walker’s ruling declaring Prop. 8 unconstitutional. The 9th Circuit Court of Appeals has upheld the decision, but the issue may soon land before the Supreme Court.

The complaint against Prop. 8 was first filed in 2009, and Gibson Dunn’s senior management made the case “the number one priority,” Olson said, putting more than 30 lawyers on the matter at any given time. Olson, a longtime conservative, led the charge with New York attorney David Boies — his onetime adversary in Bush v. Gore. Many thought the pairing unusual; Olson brushes that aside, saying the right to marry “is a matter of human rights.”

The members of the panel spent much of the evening underscoring their focus on building a fact-heavy case, which included bringing in 17 expert witnesses with specialties ranging from child development to psychology and political science to testify at trial. The opposition had two witnesses.

Drawing laughs from the crowd, McGill dubbed Boies “the great cross-examination machine, systematically disassembling” one defense witness’s view against same-sex marriage by reading to him passages from his own book in which he wrote about the benefits of adopting same-sex marriage.