President Trump announced that he's okay with a trade war late last week and he's got the tariff proposals to prove it: 25% for steel, 10% for aluminum. It’s another campaign promise fulfilled, but the decision flies in the face of Republicans in Congress and most of Trump’s own advisors. (Economic advisor Gary Cohn even quit today.) Vox’s Matthew Yglesias explains the impact of these tariffs, and the chances they could spark a trade war with our allies. He also hums a little ditty about steel. We run with it.