I think the problems associated with attrition applies to both sides.
It's quite obvious that if the US decides to engage in an armed conflict vs Iran - even a low-intensity one, it would exacerbate the problem of imperial overstretch for the US. The rapidly shrinking window of opportunity to contain or decisively engage the PRC would be permanently closed, regardless of whether the US can "win" (or claim a "win"). Moreover, any disruption in the West Asian oil supply would benefit Russia immensely in the short term. Regardless of the military outcome, it would be a strategic loss for the US.
That said, a comparable conundrum also applies to Iran. It might very well be able to "win" a conflict vs the US - defined as successfully resisting US aggression & armed regime change attempt, attriting the US armed forces, & expelling all US influence from the Shiite Crescent. However, even if it does so, its economy & infrastructure could potentially be devastated, it might even suffer a nuclear strike (if Israel or the US gets desperate). Even if US global hegemony is effectively ended by this conflict, Iran might take decades to recover. In the meantime, it would be PRC, KSA, & Russia who would benefit the most from such an outcome. Granted these countries are largely non-hostile or friendly. However, from the Iranian perspective, these other countries' rise & prosperity are hardly worth the price of devastating their own country, & diminishing Iran's standing in a post-US world.
Granted both sides have the option of "salami slicing", & responding to each other's provocations in a controlled way. However, once the shooting starts, there's no guarantee that things won't escalate out of control to all-out-war proportions.
EDIT: while we're on the subject, I think the same calculus applies to Russia & the PRC as well. Any of the 3 powers have the ability to draw the US into a war of attrition & exhausting it to the point of no longer being able to maintain hegemony. However, none of them currently have an incentive to bear the associated costs if they can avoid it, since 3rd parties are the ones that benefit the most. This is a classic "free rider" problem in politics.
It's quite obvious that if the US decides to engage in an armed conflict vs Iran - even a low-intensity one, it would exacerbate the problem of imperial overstretch for the US. The rapidly shrinking window of opportunity to contain or decisively engage the PRC would be permanently closed, regardless of whether the US can "win" (or claim a "win"). Moreover, any disruption in the West Asian oil supply would benefit Russia immensely in the short term. Regardless of the military outcome, it would be a strategic loss for the US.
That said, a comparable conundrum also applies to Iran. It might very well be able to "win" a conflict vs the US - defined as successfully resisting US aggression & armed regime change attempt, attriting the US armed forces, & expelling all US influence from the Shiite Crescent. However, even if it does so, its economy & infrastructure could potentially be devastated, it might even suffer a nuclear strike (if Israel or the US gets desperate). Even if US global hegemony is effectively ended by this conflict, Iran might take decades to recover. In the meantime, it would be PRC, KSA, & Russia who would benefit the most from such an outcome. Granted these countries are largely non-hostile or friendly. However, from the Iranian perspective, these other countries' rise & prosperity are hardly worth the price of devastating their own country, & diminishing Iran's standing in a post-US world.
Granted both sides have the option of "salami slicing", & responding to each other's provocations in a controlled way. However, once the shooting starts, there's no guarantee that things won't escalate out of control to all-out-war proportions.
EDIT: while we're on the subject, I think the same calculus applies to Russia & the PRC as well. Any of the 3 powers have the ability to draw the US into a war of attrition & exhausting it to the point of no longer being able to maintain hegemony. However, none of them currently have an incentive to bear the associated costs if they can avoid it, since 3rd parties are the ones that benefit the most. This is a classic "free rider" problem in politics.