An appeal that landed at the Supreme Court Tuesday could test the justices’ emerging concern about President Donald Trump’s aggressive deportation policies and whether he is willing to defy judicial orders.

The decision lets the Trump administration halt, for now, a program that lets migrants from Cuba, Haiti, Nicaragua and Venezuela live and work in the U.S. for up to two years.

Trump is asking the Supreme Court to let his executive order enabling mass federal layoffs proceed after lower courts blocked it.