Donald Trump campaigned hard that he would make American manufacturing great again. Actually, under President Obama, American manufacturing is booming. It's at new highs as the car industry bounced back and the shale gas boom led to a U.S. energy revolution.

But while manufacturing output has returned, blue-collar jobs have not. U.S. manufacturing employment has declined by about 100,000 jobs since Obama took office. Robots are now doing some jobs that humans once did.