The Supreme Court ruled Monday that a landmark civil rights law protects LGBT people from discrimination in employment, a resounding victory for LGBT rights from a conservative court.

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.” Justices Samuel Alito, Brett Kavanaugh and Clarence Thomas dissented.

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.

But Monday’s decision is not likely to be the court’s last word on a host of issues revolving around LGBT rights, Gorsuch noted.

Lawsuits are pending over transgender athletes’ participation in school sporting events, and courts also are dealing with cases about sex-segregated bathrooms and locker rooms, a subject that the justices seemed concerned about during arguments in October. Employers who have religious objections to employing LGBT people also might be able to raise those claims in a different case, Gorsuch said.