President Trump tweeted on Saturday afternoon that if the European Union increases tariffs on U.S. companies, the U.S. will apply "a Tax on their Cars which freely pour into the U.S."

Why it matters: This is what you'd call a trade war. This has been the primary concern since Trump announced new tariffs on steel and aluminum this week. But per Axios' Mike Allen and Jonathan Swan, tariffs are what Trump has wanted and now he's feeling like a man of steel.