Olson's comments on "Fox News Sunday" focused on U.S. District Judge Vaughn R. Walker's decision Wednesday overturning the ban on grounds it violated constitutional guarantees to equal protection and due process.
"We're talking about whether a fundamental right, something that the Supreme Court has characterized as the most fundamental relationship we have in this country, can be deprived of certain individuals because of the color of their skin or because of their sexual orientation," Olson said.
"We do not permit discrimination, inequality. That's why we have a 14th Amendment that guarantees equal rights to all citizens."
He disputed claims the decision was judicial activism.
"It's not judicial activism when judges do what the Constitution requires them to do and they follow the precedent of previous decisions of the Supreme Court," Olson said.
Asked if a single judge "overrules" the will of 7 million Californians who voted in 2008 for Proposition 8, which bans same-sex marriage, Olson replied: "That's why we have judges. That's why we have an independent judiciary. We do not put the Bill of Rights to a vote. … Our fundamental rights -- part of our Constitution -- is a separation of powers and an independent judiciary."
After three weeks' testimony in the high-profile case, Olson said, an "overwhelming record" demonstrates "individuals are being hurt and (the ban) helps no one in California and California has no rational basis for continuing this discrimination."
"We are hopeful and reasonably confident that the Supreme Court, when we get there, will agree with that."
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