Yup Biggus -and it was oil that was the issue then too. With the Americans embargoing oil supplies to Japan, the Japanese were placed in a position of backing down completely in China (unthinkable at the time to a very proud nation) or 'going for broke' while they still had credible oil reserves. The only extraordinary thing was that the Americans were apparently caught unawares by the very predictable Japanese response.
One can only hope the Americans are not caught unawares by the (let's face it) equally predictable Iranian response. With the Americans (in Iranian eyes) not far from to bankruptcy and unable to pay to maintain a credible presence in the region into the future, the Iranians see themselves filling the power vacuum - and are every bit as proud as the Japanese were in 1941.
The Iranians also see themselves as having been main players in 'seeing the Americans off' from Iraq, in much the same role the Americans played in supporting the Afghans in 'seeing off' the Soviets from Afghanistan. (It doesn't matter if many Americans will disagree with that assessment - that's how the Iraqi - yes, Iraqi - and Iranian propagandists will sell it to their people, who'll gleefully believe every word of it.)
Obama also needs to look presidential as the November election approaches - and there's nuthin' quite like an attack on a already demonised enemy to make a man look presidental. The Americans are also just begging for an excuse they can sell to the rest of the world to clean up the Iranian nuke programme.
Interesting times ahead for all of us, I fear.