It will hurt everyone, as a basic fact of economics:
1. American innovators buying components from overseas, which include many on HN and in SV, will now have to pay more, reducing their ability to innovate.
2. American consumers will have to pay more.
3. American consumers will have less innovative products, as their ability to get innovative products from other countries will be reduced, and as innovators in both the U.S. (see #1 and #4) and in other countries will be hamstrung.
4. American innovators will face less competition, which is certainly not what leads to innovation; it leads to profit-taking based on market power, not meritocratic competition.
5. Reduced international cooperation and trade will reduce American innovators ability to sell abroad; the U.S. is only 5% of the world's population; the other 95% of the market is elsewhere. Cooperation and trade will not only be reduced as a direct effect, but also as a result of the U.S. appearing to be an unreliable partner, and as a result of other countries responding in kind by pulling out of treaties when they find any problems.
6. As reduced trade hurts economies here and abroad, Americans will pay more, have fewer people to sell to, resulting in lower wages and fewer jobs.
Finally, the greatest American innovation is democracy, the belief that all men are created equal and that's what leads to prosperity. That innovation has resulted in an explosion of peace and liberty unlikely anything the world has ever seen, and it has, as a secondary side effect, brought an explosion of prosperity unlike anything the world has ever seen. The U.S. is now purposefully killing that innovation.