Catherine Rampell: Trump has been playing right into China's hands

If this is how we show China who’s boss, China has just learned it has a pretty dumb boss.On Thursday, President Trump signed sweeping new tariffs on steel and aluminum, against the urging of economists, allies and most of the manufacturing, retail and home-building industries. This policy will likely destroy American jobs both in industries that use steel and aluminum and in ones that may soon be hit by retaliatory measures from other countries.But no matter all that. Trump really, really