again: i'm an mmt advocate. this swing to social conservatism on the left pisses me off, sure, but i'm a strict socialist, and i don't have any patience for anybody pushing hayekian market theory.
in canada, we could print as much as we want - we'll just have to take a hit in the credit rating. there's nothing stopping us from doing it, and it's not likely to affect the currency all that much on it's own. but, when the credit agencies step in, they institute sell-offs and drive the price down. it's real in effect, but it's artificial in construction; it's not printing the money that's going to kill us, it's the ratings agencies that will come in and decimate us for their pound of flesh, afterwards.
that just doesn't matter in the united states, and it's never going to unless they either make a stupid decision to institute their own decline (ie. stop printing money) or they get outprinted by somebody bigger and badder than them.
now, if that does happen, if the floodgates open, if the agencies are set loose on america, you're going to have absolute carnage. granted. america will end up subject to imf austerity regimes, forced to sell-off assets - the whole thing. how much do you think the saudis would pay for the statue of liberty?
but, they're really in control of this - so long as they don't stop printing.