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 people because of their sexual orientation or gender identity.

"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."

The decision was a defeat not just for the employers, but also the Trump administration, which argued that the law's plain wording compelled a ruling for the employers. Gorsuch, a conservative appointee of President Donald Trump, concluded the opposite, and Trump said Monday he accepted the court's "very powerful decision."

Gorsuch was joined in the majority by Chief Justice John Roberts and the court's four liberal members. Justice Brett Kavanaugh, Trump's other Supreme Court pick, dissented, along with Justices Samuel Alito and Clarence Thomas.