This is a particularly extreme version of the “unitary executive” doctrine that conservative legal scholars sometimes appeal to (especially when there’s a Republican president), drawing on the notion that the executive branch of government — including the federal police agencies and federal prosecutors — are a single entity personified by the president.
But to push that logic into this terrain would not only give the president carte blanche to persecute his enemies but essentially vitiate the idea that there are any enforceable laws at all.
(via Trump’s memo response to Mueller’s interview subpoena is tyrannical – Vox)
This isn’t new. This came up during Bush43.
