What are you talking about? Are you high? Domestic sources of product will come on line or unused factory capacity will come on line. Economic active will go thru the roof!!
This happened in 1932 when the US replaced Hoover with FDR, leading to nearly a century of left-wing economic policies. The whole thing is a bad idea.
Smoot-Hawley had a tiny marginal affect on the Great Depression.
Time will tell. I don’t believe you are right about an economic boom — but if the country does move toward protectionism, I hope you are. Or at least that income taxes and regulations will be reduced dramatically, counteracting the contractionary effect of a tariff.
You’re right about domestic production growing to fill in the gap left by the missing imports. But the catch is that it will be at higher prices. As consumers pay higher prices for those goods, less money is available for everything else, and the pain gets spread throughout the economy. The total pain distributed throughout the economy will be greater than the total dislocation caused by the original job losses.
That’s why, even with increased domestic production in targeted industries, GDP overall will drop, and total number of jobs will drop with it.