Trump flunked Econ101 with the rest of the democrats. 
“Tariffs are Taxes” is the title of a National Review op-ed by Larry Kudlow, Art Laffer, and Stephen Moore:
One of the ironies of trade protectionism is that tariffs and import quotas are what we do to ourselves in times of peace and what foreign nations do to u s with blockades to keep imports from entering our country in times of war. Or consider that we impose sanctions on U.S. enemies such as North Korea, Russia, and Iran because we want them to feel the economic pain of being deprived of imports.
But now we are imposing sanctions on our own country, putting up tariffs supposedly to make Americans more prosperous. If ever there were a crisis of logic, this is it.
President Donald Trump genuinely believes that his steel and aluminum tariffs will save thousands of blue-collar jobs. And we know from our interactions with him that he truly cares about these workers in Pennsylvania, Ohio, and other Rust Belt states. We do, too, and we don’t want factories to shut down.But even if tariffs save every one of the 140,000 or so steel jobs in America, they put at risk 5 million jobs in industries that use steel.
These producers now have to compete in hyper-competitive international markets using steel that is 20 percent above the world price and aluminum that is 7 to 10 percent higher than the price paid by our foreign rivals.Steel and aluminum may win in the short term, but steel-and-aluminum users and consumers lose.
Tariffs are really tax hikes. Since so many of the things American consumers buy today are made of steel or aluminum, a 25 percent tariff on these commodities may get passed on to consumers at the cash register. This is a regressive tax on low-income families. Meanwhile, up to 5 million jobs will be put in harm’s way. And if U.S. steel-and-aluminum-using industries sell less to foreigners, the trade deficit goes up, not down.
Trump should also examine the historical record on tariffs. If he does he’ll see they have almost never worked as intended and have almost always delivered an unhappy ending.