Supreme Court rules Germany can't be sued in Nazi Art case

[Donerail]

How would such a judgement be enforced anyhow?

You could enforce a US judgment against their assets in the United States. This is often tricky, b/c most of the judgments people get in the US against foreign states are against countries like Iran and Syria that don't maintain a lot of assets in the US, and there are some protections for things like embassies. In this case, it should be fairly easy — congratulations on your new Volkswagen.