Earlier quoted context omitted.
The dollars are worth whatever the relative foreign policies set. If China has a policy to depreciate against the dollar, by printing Yuan and buying dollars with them (what happens now) then the dollars end up being "worth" more, but the underlying capacity to produce of the U.S. hasn't increased, indeed it starts to decrease as people start to buy cheaper foreign output. So it's a bit disingenuous to say "well, peo…
The US manipulates the currency market in other, more powerful and more fundamental ways, by controlling the global currency. You do not need to hold foreign reserves, you do not need to pay exchange commissions, you are not blocked to do business with third parties by having capital flows stopped ...
This is why the U.S. is the reserve currency, and it is also why we have a trade deficit, because as the rest of the world's capital pours into the U.S., that forces our currency to be overvalued enough to have an equal sized trade deficit on the way out.
Whereas you seem to think that that the U.S. "manipulating" it's currency by making U.S. currency more attractive to hold for foreigners -- is somehow a counter or offsets what China is doing, which is making its currency less attractive to hold.
But it's not, these two work together to cause the same distortion and large trade deficits.