The exodus appeared to be part of an effort by President Trump to clear out the department and steer it in a “tougher” direction.

Many immigration policy changes require congressional approval, however.

Visas: The federal government wants to issue more visas for foreign workers to take temporary jobs in housekeeping, landscaping and other fields, even as Mr. Trump threatens to seal the border with Mexico, where most of those workers come from.

In court: A California judge on Monday blocked the president’s efforts to force asylum seekers to wait in Mexico while their cases are adjudicated by the immigration courts.