The judges will be expected to clear at least 700 cases a year to receive a “satisfactory” performance rating, a standard that their union called an “unprecedented” step that risks undermining judicial independence and opens the courts to potential challenges.

Atty. Gen. Jeff Sessions has promised to stiffen immigration enforcement partly by moving more aggressively to clear a backlog of more than 600,000 cases pending before the Executive Office of Immigration Review, the federal court system that adjudicates immigration cases.

Some immigrants facing deportation wait years for a court date, but they are typically authorized to work in the United States to support themselves during that time, an arrangement that critics view as an incentive to illegal immigration.