WASHINGTON (CBSLA/AP) — The Supreme Court ruled Monday that a landmark civil rights law protects gay, lesbian and transgender people from discrimination in employment, a resounding victory for LGBT rights from a conservative court.

“This is an incredible victory,” Terra Russell-Slavin, of the Los Angeles LGBT Center, said. “And while it was definitely time for this to happen, I think we are all overjoyed and, frankly, pretty excited that it happened under a conservative-leaning court.”

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The court decided by a 6-3 vote that a key provision of the Civil Rights Act of 1964 known as Title VII that bars job discrimination because of sex, among other reasons, encompasses bias against LGBT workers.

“An employer who fires an individual for being homosexual or transgender fires that person for traits or actions it would not have questioned in members of a different sex,” Justice Neil Gorsuch wrote for the court. “Sex plays a necessary and undisguisable role in the decision, exactly what Title VII forbids.”

Loyola Marymount Professor Jessica Levinson says Congress did not intend this broader interpretation of the word “sex” when it passed the 1964 law.

“Just looking at that one word – ‘sex’ – and deciding are we going to read it narrowly to basically mean it only protects you if you’re fired because you’re a woman, which is the quintessential example or does it also protect you because you’re fired or discriminate against because you’re transsexual or because you’re gay,” Levinson said.

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The decision written by Gorsuch – a historical conservative – was the first pro-LGBT rights SCOTUS decision that wasn’t written by retired Justice Anthony Kennedy, according to Levinson.

Justices Samuel Alito, Brett Kavanaugh and Clarence Thomas dissented.

“The Court tries to convince readers that it is merely enforcing the terms of the statute, but that is preposterous,” Alito wrote in the dissent. “Even as understood today, the concept of discrimination because of ‘sex’ is different from discrimination because of ‘sexual orientation’ or ‘gender identity.'”

Kavanaugh wrote in a separate dissent that the court was rewriting the law to include gender identity and sexual orientation, a job that belongs to Congress. Still, Kavanaugh said the decision represents an “important victory achieved today by gay and lesbian Americans.”

The outcome is expected to have a big impact for the estimated 8.1 million LGBT workers across the country because most states don’t protect them from workplace discrimination. An estimated 11.3 million LGBT people live in the U.S., according to the Williams Institute at the UCLA law school.

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