Can We Sue Germany for WWII?

[Thumpalumpacus]

What are they going to do, come move the buildings they own here over to SA? Perhaps seize Chase by force of arms?

I don't think you're thinking this through. The interconnection of the world's economy means that every country worth mentioning has hooks on every other country worth mentioning -- especially America, a favorite investment destination. We don't need Saudi cooperation to impound funds generated in America by Saudi investments.

But then the Saudis could decide to stop selling us oil, and then we'd have a real problem on our hands.  What you've described is more of a cold war, not a lawsuit.  And I really don't think that pissing off Saudi Arabia is a good idea.

If we freeze their assets here, there's not a damned thing they can do about it.

We source very little of our oil from the Saudis, and given how they're glutting the market trying to put both American frackers and Russian drillers out of business -- with the deficits that such price drops imply for the Saudi budget -- I think we're in the catbird seat there. They'd have to raise prices (right now at $49/bbl), while fracking needs $45/bbl to be profitable, and Russian drilling only $40/bbl. If they raise prices to help their budgeting, they open the market even further to competition. The Saudi budgeting has been predicated on oil at around $60/bbl, and they're already backing down on their welfare-state in order to trim costs.

I'm not describing a cold war. I'm describing a physical fact, backed up by economic muscle. If the Saudis lost a hypothetical lawsuit to 9/11 family members, the judgement could and likely would be enforced by attaching Saudi assets in the US. And if they got sore about it and wanted to retaliate using oil, they'd only make the market more open to both American and Russian producers.