This thread has frayed and is getting far from the question put by mg.
The U. S. is not a dictatorship, and diversions of supply is faced with jurisdictional boundaries and legal contracts.

Motorized gasoline trucks (and rail tankers) are under contract, essentially tied to the areas they serve and cannot be shifted to serve an emergency situation. Legal and logistical problems abound. Change their destination also creates a shortage in the area they are programed to serve.
Pipelines could be provided with emergency equipment to facilitate flow in areas with emergencies (added costs). Pipeline product is also under contract, and forced diversion only creates shortages elsewhere.
Marine shipment is similarly bound by contract, and the majority of tankers are not subject to U. S. wishes.

A couple of comments on side issues raised here.
The United States has a small and dwindling supply of crude oil sources, unless shale gas extraction is made a priority. What this will do to aquifers and land use in areas with organic-rich shale is scary to contemplate. Lead-in time to provide a plentiful supply would be several years, and the cost will be high monetarily (expensive product) as well as environmentally.
There are reserves in the Gulf of Mexico, but at great depth. Better engineering to prevent another BP disaster is possible, but expensive.

There are areas in the world with more easily obtainable raw product e. g., Alberta-Saskatchewan oil sands and the raw or refined product from countries with crude petroleum reserves. Use them first!

It will require a 50-year lead-in period before so-called environmentally friendly energy is fueling the country. Our government policies are not pushing in this direction and we have wasted money on unnecessary wars; out debt already is enormous. People are feeling the pinch; it is doubtful that they would approve the costs involved and support legislators who would vote the funds necessary to replace coal and petroleum any time soon.

Petroleum producers on the whole work on a 10-12 percent margin; none is making huge profits for the company. The money goes to shareholders large and small, the same as with any other business, with a small percentage held to promote growth. They would divert to other energy sources, but incentives are required. The object of business is profit- the product type doesn't matter. Some majors already have stakes in other energy sources.
Great shifts in employment would occur- all the downline suppliers and users are affected.

Speculation does affect prices of futures on many materials, including wheat, rice and other grains, minerals and all raw materials that are traded publically on the stock exchanges. Shortages generate higher prices. How would one go about dismantling the world's trading system?