Russia, Iran, china and others have positioned themselves and pushed the US into a corner so that this can happen. There is no way we could outright attack Iran now without the UN taking action. Remember not to long ago, Trump blasted the UN? The US is being put in its place and there is not much the US gov can do about it. Hence the extreme buy-back of treasuries by the FED. The US used to be able to just pressure countries into accepting and bowing to its hegemony, this is no longer the case.