When I visited Alaska this summer, I was delighted,
and then left feeling somewhat apprehensive, upon
seeing the Alaska Pipeline closeup.
You see, the pipeline provides upto 20 percent
of your domestic crude-oil output; roughly one million
barrels of oil flow through it daily.
I checked out a pdf file on America's crude-oil production,
import quantities and consumption.
The approximate values are around these numbers.
(1) Total daily crude-oil supply for America's needs (domestic and import supply combined) : somewhat over 15,000,000 barrels/day.
(2) Total daily domestic crude-oil production in America:
about 5,000,000 barrels per day.
(3) Total daily OPEC crude-oil imports: somewhat under 6,000,000 barrels per day.
[many OPEC nations are unfriendly to America]
(4) Total daily refined crude-oil [gasoline, diesel] needs in the USA:
Approximately 10,000,000 barrels per day [gasoline, diesel].

This data, however generalized, should make you nervous.

Take a look at Alaska's Oil Pipeline for instance.
Built in the 1970's; it's designers [wisely] planned for and built the
pipeline to withstand forest fires, earthquakes, floods, and idiots with guns.
However...The pipe is only 4 feet in diameter, and the steel is less than 1/2 an
inch thick....Can it withstand an Al Qaeda attack if they use dynamite or C4?
An if it can't, how long will it take to repair? How much effect will that have
on the price at the pump?