"That's an incredibly serious thing if people think that the president of the United States can tell heads of law enforcement agencies, based on his own whim or his own personal preferences or friendships, that they should or should not pursue particular criminal cases against individuals. That's not how America works."

Previous Quote

Obstruction, basically, is whether you corruptly influence, obstruct or impede the administration of justice. You tell a chief law enforcement officer get, you know, back off my friend - or I hope you back off my friend and then when he doesn't, you fire him, clearly, that isn't - that is - fits the behavior of obstruction. The question of whether or not you can prosecute the president is open.

— Keith Ellison