Lower courts had blocked the travel ban, announced in September, as well as two prior versions, in challenges brought by Hawaii and others. The Supreme Court had allowed the ban to go largely into effect in December. The ruling empowered Trump at a time when he faces controversy over his approach toward illegal immigration along the US-Mexico border. The court held that the challengers had failed to show that the travel ban violated either immigration law or the Constitution's First Amendment prohibition on the government favoring one religion over another. "The ruling will go down in history as one of the Supreme Court's great failures," said Omar Jadwat, a lawyer for the American Civil Liberties Union.