President Donald Trump's effort to ban immigrants from several Muslim-majority countries heads to the Supreme Court today, which will decide if his argument asserting national security interests was tainted by religious bias.
The case, known as Trump v. Hawaii, will address the president's broad powers to set immigration policy, which the administration says permit Trump's travel ban, one of his hallmark policies since taking office in January 2017.
Legal experts say the court is usually loathe to rule on executive powers.
But the travel ban's focus on Muslim countries has left Trump the target of allegations that it violates constitutional religious protections, which led lower courts, including the federal court in Hawaii, to rule it illegal.
"This case has everything: weighty constitutional issues, complex statutory questions, and a fight over whether there are any real limits on a president's power to control immigration," said Cornell University law professor Stephen Yale-Loehr.
"Whichever way the court rules, the decision will have profound implications for Americans, immigrants, and the president."
They noted that during the election the previous year Trump repeatedly attacked the Muslim immigrants, whom he said "don't assimilate" and "hate us."