The US Supreme Court on Monday delivered a watershed victory for LGBT rights and a defeat for President Donald Trump’s administration by ruling that a longstanding federal law barring workplace discrimination protects gay and transgender employees.

The landmark 6-3 ruling represented the biggest moment for LGBT rights in the United States since the Supreme Court legalised same-sex marriage nationwide in 2015. Two conservative justices joined the court’s four liberals in the decision: Neil Gorsuch, a 2017 Trump appointee who wrote the ruling, and chief justice John Roberts.