The Trump administration’s travel ban presents a complex case for immigration advocates who have challenged previous efforts by President Trump to close the U.S. to certain foreigners. Trump needed multiple bites at the apple during his first term before the Supreme Court upheld the third version of his so-called Muslim ban in 2018.

Iran appeared to have rejected a key element of an American proposal aimed at breaking the deadlock in the negotiations over the future of the country’s nuclear program.

The ban mostly blocks travelers from countries in Africa and the Middle East.