Mr. Miller is pushing for new ways to squeeze the lives of illegal immigrants and those with legal status, such as making it harder to get public housing or other benefits. He has targeted those with refugee status, and is putting the finishing touches on a rule to block green cards for immigrants who might need assistance.

He remains focused on ramping up deportations of noncitizens to faraway countries, with the hopes of encouraging immigrants still in the United States to leave voluntarily, and is working with politicians in various Republican states to pass anti-immigrant laws.