Catherine Rampell: Trump’s two worst economic ideas have collided

At 12:01 a.m. Friday, President Trump's two worst economic ideas finally collided — and made each other even worse.To be sure, there are a lot of terrible economic theories espoused by this president (tax cuts pay for themselves, government shutdowns are fun, scam artists should roam free, etc.). But the specific bad ideas I'm referring to are:1. Trade wars are good and easy to win; and2. It’s smart for the president to publicly bash the Federal Reserve.Last fall, Trump began loudly