I assume you mean OP?
> The entire world (including the US federal government) has taken a short position on the US dollar
I read this as a prediction of some type of crisis.
Anyway, wrt the US Federal Government, having government debt is not that same as having a short position. For one, the US Fed govt's revenue (i.e. tax collection) is denominated in the same USD as the debt. So if USD goes up, tax collection go up.