What is plenary authority, the phrase that caused Stephen Miller to freeze up during CNN interview?

What is plenary authority, the phrase that caused Stephen Miller to freeze up during CNN interview? - Miller suggests Trump wields absolute power over decisions to send in the National Guard, before s ...

What is plenary authority? Trump adviser's remark raises eyebrows

Miller appeared to fall silent immediately after talking about plenary authority on a live TV interview. The network later explained there was a technical issue.