If we or Israel attack Iran it would take maybe 5-8 million barrels of oil off the market. It would send the price so high it would essentially seize up global commerce. There would, with out a doubt, be huge diesel shortages, very very long lines at the gas station and are market crash of some magnitude. Given the current condition of the market, quite huge in my estimation.
Out of our three biggest supplier’s, Mexico’s production is falling at an alarming rate, Canada can’t ramp up and Venezuela is slowly declining. This has caused a bottle neck with shipping since we now have to go a much further distance for oil thus needing more tankers to keep up with demand. Also, add the fact that tankers are in short supply and moving slower to be more fuel efficient makers the matter worse. Basically, if demand does not precipitously drop, they will not even get us oil fast enough to keep up with a slightly declining demand. The question is what is the number to knock the middle class on the bus, if they are lucky enough to have one where they live?
Attacking Iran is quite literally insane and the market is reflecting that by just the mention of the possibility.