A federal appeals court ruled for the first time Tuesday that the 1964 Civil Rights Act protects LGBT employees from workplace discrimination, setting up a likely battle before the Supreme Court as gay rights advocates push to broaden the scope of the 53-year-old law.

The 8-to-3 decision by the full 7th U.S. Circuit Court of Appeals in Chicago comes just three weeks after a three-judge panel in Atlanta ruled the opposite, saying employers aren't prohibited from discriminating against employees based on sexual orientation.

The 7th Circuit is considered relatively conservative and five of the eight judges in the majority were appointed by Republican presidents, making the finding all the more notable.

The case stems from a lawsuit by Indiana teacher Kimberly Hively alleging that the Ivy Tech Community College in South Bend didn't hire her full time because she is a lesbian.

In an opinion concurring with the majority, Judge Richard Posner wrote that changing norms call for a change in interpretation of the Civil Rights Act, which bars discrimination based on race, color, religion, national origin or sex.

"I don't see why firing a lesbian because she is in the subset of women who are lesbian should be thought any less a form of sex discrimination than firing a woman because she's a woman," wrote the judge, who was appointed by Republican Ronald Reagan.

The decision comes as President Donald Trump's administration has begun setting its own policies on LGBT rights. Late in January, the White House declared Trump would enforce an Obama administration order barring companies that do federal work from workplace discrimination on the basis of sexual identity. But in February, it revoked guidance on transgender students' use of public school bathrooms, deferring to states.

Hively said after Tuesday's ruling that she agreed to bring the case because she felt she was being "bullied." She told The Associated Press in a telephone interview that the time has come "to stop punishing people for being gay, being lesbian, being transgender."

"This decision is game changer for lesbian and gay employees facing discrimination in the workplace and sends a clear message to employers: it is against the law to discriminate on the basis of sexual orientation," said Greg Nevins, of Lambda Legal, which brought the case on behalf of Hively.

Ivy Tech said in a statement that its policies specifically bar discrimination based on sexual orientation and that it denies discriminating against Hively, a factual question separate from the 7th Circuit's finding regarding the law.