Presidents have been squabbling with Congress for as long as we have had presidents and Congress. But Donald Trump, smasher of convention, may be giving us something we haven't seen in our lifetimes: a president in all-out war against a Congress his own party controls. Why is he doing it? He still doesn't seem to have managed to wrap his head around the idea that Congress is a collection of 535 egos, fears, and agendas, ones that may or may not line up perfectly with his own at any given moment.