Because, it just might not be in their strategic interest to tweak our noses after that.
At least in the short term.
Key to his scenario, though, is this:
- ...most of America’s allies (protectorates) in the Middle East would welcome a strike on Iran, since they either share our paranoia about Iranian nukes, or dread the rise of Shi’a influence in the region.
As Billmon notes in a postscript, even Saudi Arabia is apparently trying to put the brakes on the slide to (metaphorical?) Armageddon. But I'm more interesting in the other, declared Muslim nuclear power --- Pakistan, where a (currently) pro-American leader is clinging to power, while Dubya just went out of his way to snub the guy by offering a nuclear deal to nuclear rival, India --- while the intelligence service, which created the Taliban, seems to be reverting to form.
And how will they respond to a nuclear attack on a Muslim state? An attack on Iran could well create a Muslim nuclear state with a government thoroughly inimical to American interests in the region and throughout the world --- in Pakistan.
Which is, of course, to completely neglect Iran's own retaliatory capabilities, which Billmon must avowedly soft-pedal to make his scenario work. Given Iran's ties to the multiple Shiite militias which seem to currently comprise the bulk of what is ludicrously described as "the Iraqi armed forces", that could get very, very ugly...