Remember how much toppling Sadam Hussein, killing a million Iraqis, rounding up and torturing thousands of random Iraqi civilians, destroying most of the country's vital infrastructure, and selling their oilfields to American companies at bargain prices helped Iraqis? It's going to be the same for Iran. There's going to be massive suffering.
But at the end of 1 milion deaths (est.) Iraqi oil was dollarized.
Saddam had been selling dollars for euros and talking about shifting his oil to other currencies for years. 2003 put an end to that - it was literally the first thing that was done by the provisional Govt. was to make sure all Iraqi oil was sold in dollars.
The Petrodollar was not in jeopardy anymore, and for the post-1971 system, that was essential. Same thing is now happening with Iran and Venezuela. The real goal is - China must not be allowed to have substantial sources of energy that are not priced in dollars.