The United States is one of the world's largest manufacturers as is.. Yes we had a lot of manufacturing go to China and other countries, but we still manufacture a HUGE amount of stuff right here. Most of it is higher-margin, industrial componentry, all manner of things essential to the functioning of the economy and society but not generally stuff you will find at the likes of Target and Wal-Mart. One thing that is made in China a lot that we need to move somewhere else is a lot of our pharmaceuticals.
Regarding tariffs on China, that depends. China has had a strategy of subsidizing certain industries and then flooding the market with under priced products from said industry so as to kill off competitors in the U.S. Some of these industries are critical to national security, for example steel and aluminum. The Chinese had been flooding industry with very cheap steel and aluminum, in a bid to dominate those industries but also likely to kill them off in the United States in particular. Losing our domestic sneaker or T-shirt manufacturing to China is one thing, but industries like steel and aluminum are critical to infrastructure and defense. So Trump was right to put tariffs on the Chinese over those IMO. Critics at the time accused him of starting a trade war with China, which I found perplexing as he was responding to the trade war that China had/has long been conducting against the U.S. He sought a decent balance in the end I think because he ended up criticizing the argument of using national security to restrict companies from doing business with China. GE Aviation was nervous he would stop them from being able to sell jet engines to China, and he said no, that America is open for business and the national security argument gets used too much.
Regarding the TPP, Trump's argument was that engaging in a large multilateral deal was foolish because if one member starts cheating, it is hard to do much about it, whereas if you negotiate individual deals with all of the countries, then if any one country cheats, you can cancel the deal. I don't know if he was right or wrong ultimately there, but it is an interesting point.
