No one can cut off the US oil supply.
Well, if the US invests on being able to use its own oil without mixing with anything else, the can become true.
Not to mention they could simply seize oil haulers for themselves with their navy.
A few times, yeah. The world won't react well to the US specializing into constant piracy.
And you can get 1F capacitors in bulk from China for a few dozen dollars each.
Those things are still dangerous and scary. The 1T magnet way more so than the capacitor.