i'm learning about gas!
okay, this is a fairly old idea--buy gas from distributors who sell primarily domestic product and we can help speed up the end of the war. but, that isn't really how things panned out and the war seems based on myriad other factors now that buying U.S. sourced gasoline can't change much. however if you are still interested, here is the link to which companies derive what percentage of their product from the persian gulf:
department of energy site
retailers such as citgo (venezuelan owned) are at zero percent because they import most, if not all, of their product from venezuela; surprisingly, canada sells us the most foriegn-pumped raw product. does this mean that if you fill up at exxon/mobil 28% of the gasoline that goes in your tank will be from the persian gulf? no...as petroleum is petroleum is petroleum and it all gets refined together and sent out to retailers as a giant melange of foriegn and domestic sourced product. so you really don't know exactly where the gas comes from when it goes into your car; you can only know that said company bought x amount of raw product from y region in any given year.
and that is our petrochemical lesson for the day, people.