The U.S. Supreme Court ruled against the Trump administration Monday when it said a century-old law banning so-called obscene or immoral trademarks is unconstitutional.
All nine justices agreed that the 1905 Lanham Act violated the First Amendment guarantee of free speech.
"There are a great many immoral and scandalous ideas in the world, even more than there are swear words. And the Lanham Act covers them all," Justice Elena Kagan wrote. "It therefore violates the First Amendment."
While all the justices agreed with Kagan, three partially dissented. Justice Sonia Sotomayor wrote the government will now have to register "the most vulgar, profane, or obscene words and images imaginable."
The Justice Department wanted to keep the 1905 law in place, arguing that the American marketplace will be flooded with dirty language trademarks.
Monday's decision centered on a California designer who wanted to register FUCT as a brand name for his clothing.
The federal U.S. Patent and Trademark Office turned him down, saying his brand name looked and sounded too much like a well-known obscene word.