It costs American blood (thank God, not much; but who are we to say, "Mrs. Jones, your only son must die so that we can buy oil from Kuwait, rather than drilling fields of empty, godforsaken ice") and American treasure (unless Carrier Battle Groups sail around the globe for free).
Cut the Persian Gulf loose, promise them no reduction in Economic Risk Premium subsidized by American Military Presence, and we'll see how "cheap" their oil is... if they can stop killing eachother long enough to drill the stuff.
Meanwhile, no eskimos have recently gotten their dander up and flown jetliners into skyscrapers.
So let's drill there, instead.
Doesn't cost Blood, doesn't cost Treasure for carrier battle groups.
Now that's cheap.
The Persian Gulf provides less then 12% of our oil consumption. If we all cut back on consumption we can boycott their oil no problem. I'm all for it.
But unless we're willing to cut loose our 'allies' and the rest of the world economy, Mrs Jones's son will still be stationed in harm's way to protect the flow of oil through the Persian Gulf.