The thing about oil is that it is an international commodity market. Generally one can't just say I want to buy that barrel from Canada and not one from Saudi Arabia (even though the politicians may want you to think that's how it works). BP, for example, drills all over the world. If one major area destabilizes, it impacts the entire market. In the 70s when the OPEC oil embargo took place, we were easily drilling enough domestically to take care of our needs, but that embargo crashed the market supply.