America underestimates the difficulty of bringing manufacturing back

Under normal circumstances, when a country is running a massive surplus, their currency should appreciate, weakening their exports and thus recalibrating trade balance back to zero. That isn't happening right now, because China (and other surplus nations like Germany and Japan) relies on buying massive amounts of US treasuries to weaken the Yuan. That's one of the reasons why the US dollar is the reserve currency. It has to be, because only the US has an economy large enough to provide high-yield, low-risk treasuries and is willing to do so.

Trump's tariffs would theoretically rebalance trade on the long term, albeit in a highly destructive manner. But the more diplomatic solutions as proposed by other commentators like Catherine Tai, Yanis Varoufakis or Michael Pettis would be the introduction of capital controls to stem the demand for US treasuries, or better, the reintroduction of Keynes' proposal of the International Clearing Union back in 1945. The ICU's role would be to actively balance global trade surpluses via the international currency bancor, of which would have fixed control of FX rates rather than relying on FX markets to punish surplus nations and help deficit nations respectively. As for nations outside the Union, they would just get treated similar to the USSR.