The Trump administration on Friday took one of its most aggressive steps yet to legalize anti-transgender discrimination by telling the Supreme Court that federal law allows firing workers solely for being transgender, arguing a Michigan funeral home could fire a transgender woman because she wanted to wear women’s clothing on the job. Although the administration was expected to take the stance — and had previously said firing workers on the basis of gender identity is legal under federal law — the latest court filing asks the nation’s top court to establish federal case law in a potentially sweeping setback for LGBTQ rights nationwide. The case is a dispute over the word “sex.” Title VII of the Civil Rights Act of 1964 bans workplace discrimination because of sex, but the court’s justices have never decided what, precisely, the term means for LGBTQ workers.