The hour-long hearing, conducted by telephone among three West coast judges at 6 p.m. ET, will determine the immediate fate of the nationwide temporary restraining order against Trump’s travel ban.

Trump has only been in office for 17 days, but his Justice Department is already embroiled in a high-stakes legal battle that could affect hundreds of thousands of people and the direction of his presidency.

Attorneys general for Washington and Minnesota, which challenged the executive order, say that the temporary restraining order should remain in place because the President had “unleashed chaos” by signing the order.