Purchasing your gas from companies that don't import oil from the Mid East will lower the overall cost of gas - only if done in large numbers!
Companies that import Middle Eastern oil:
Shell............ 205,742,000 barrels
Chevron/Texaco......... 144,332,000 barrels
Exxon/Mobil............... 130,082,000 barrels
Marathon/Speedway... 117,740,000 barrels
Amoco.........................
Companies that don't:
Citgo.......................0 barrels
Sunoco...................0 barrels
Conoco...................0 barrels
Sinclair.................0 barrels
BP/Phillips...............0 barrels
Hess................0 barrels
ARC0......................0 barrels
(information from the Dept. of Energy)
If you live in Boise; your best bet is 7-Eleven, Stinker & Smokin Hot Deals gas stations - they server up Citgo and Sinclair gas.