This is actually a pretty clear extrapolation from a point I've been making since back in March. See here and here. If you want to understand Trump, read Nelson W. Polsby's Consequences of Party Reform. I'll just add a few brief comments about the oddity of how relatively strong the president is on foreign policy, and how relatively weak the president can be legislatively. Yes, Trump really could be a Carter legislatively, unable to convince Congress to impose the tariffs he wants, while sending the military around the world with nobody to stop him. Chain of command versus checks and balances. The War Powers Resolution of 1973 gives the President 90 days, effectively, to do whatever he wants with the military before Congress imposes any limits, and that's before we talk about nukes, which don't pass through the generals the same way. Oh, and do those restrictions mean anything in the wake of Syria and Libya anyway?
So, yes, Trump might really turn into Jimmy Carter. Legislatively. On foreign policy? Who knows?
*Did'ya know I predicted he'd be on the ticket back in April? Did'ya? Huh? Huh?