The rationale I suppose is they can try to develop local manufacturing by making foreign goods so expensive that its cheaper to make them at home, but they don't understand the amount of labour and time and planning that went into it on the part of China, where Mao developed the industrial base and secured China's sovereignty with 两弹一星 (two bombs, 1 satellite), Deng introduced western capital to develop those industries, and then it still took the better part of a half century to get all that to pay off. The current American leadership simply doesn't understand the sheer logistics of making your own stuff, you can't just go well if Chinese goods now cost 3x as much we can make stuff in America. That's gonna take decades (not that American capitalists have the will to do so in the first place) and Americans will have to go without until then, and the baby treatlerites aren't going to accept that. How are you gonna do import substitution with no substitutes? American companies are just gonna try to circumvent the tariffs by moving manufacturing to even cheaper countries or slapping a made in Vietnam sticker on a Chinese product and hoping customs doesn't look too hard.