My thoughts are that China is no longer recycling their profits into US treasuries, and the BRICS countries seemed to be heading down the same path. The US cant sustain high interest rates and needs people to buy this debt, hence there is a lot of talk of tariffs and a "green new deal" type of tariff system on emissions in order to derive additional revenue without increasing taxes on citizens. Citizens want entitlement programs that are ponzi schemes that have already been spent long ago, but they dont want additional taxes, and so you need a scheme to get around their votes.
The same thing happened after the great depression where they rebased gold to a lower value after confiscating it, and some speculate it created an environment ripe for WWII. Our system of printing money tends to increase aggregate demand while misallocating capital, like houses in 2008, and thus it ends in suffering.