But in a systematic and less visible way, his administration is following a blueprint to reduce the number of foreigners living in the United States — those who are undocumented and those here legally — and overhaul the U.S. immigration system for generations to come.

Across agencies and programs, federal officials are wielding executive authority to assemble a bureaucratic wall that could be more effective than any concrete and metal one. While some actions have drawn widespread attention, others have been put in place more quietly.

The administration has moved to slash the number of refugees, accelerate deportations and terminate the provisional residency of more than a million people, among other measures.