Depends what 'sovereign' implies. The will of the people? Or maybe the will of those that lobby government the hardest (e.g. oil companies)? If the latter, then export bans might not arrive anytime soon.
Sovereign doesn't mean any of those in this context. It means that the US can set its foreign and domestic policies as it pleases. How it decides those policies is another matter.
'Sovereign' here means that the US govt is able to impose export restrictions, not that the People's will or special interests' desires are relevant. Of course 'can' != 'will'.
For example, in the UK Parliament is sovereign, not the people. That's effectively how it is in representative democracies or republics where there is no fast representative recall mechanism.
The U.S. Constitution doesn't say that Congress is sovereign, but the effect is the same. For that matter, the U.S. President has a great deal of power.
