[peterwwillis]

They don't have a right to do it, but there's nothing to stop them.

A foreign power can have any law it wants, and no other foreign power has to respect it. You can try to sue them, but sovereign immunity, and foreign sovereign immunity, stops almost all of these attempts. The exceptions generally are human rights abuses (by the same state doing the suing...) and commercial transactions.

In this case, the USG stole from money launderers in a foreign country. So not only can people in the US not sue the USG over it (sovereign immunity), people in the Ukraine can't sue the USG over it (foreign sovereign immunity). The thieves would have the best claim, but it doesn't work out well when you claim your illegal business was stolen from. And since it's a foreign power, if the US balks, it would be covered under international law, and guess who enforces international law?

[bdowling]

If your property is wrongfully seized by the government due to some criminal activity, you can file a claim to get it back. This happens all the time when a criminal is caught with stolen goods. The thieves do not have the best claim.

It may take some time and effort to get the property back, but there is a process.

[peterwwillis]

Assuming the govt took the money under the auspices of a criminal forfeiture (which I assume because the company was supposedly for money laundering), you would basically need to prove a paper trail to show what specific part of the money they seized was yours, and even then who knows if there isn't a loophole that allows them to basically not respond if the forfeiture was of a foreign company on foreign soil. They took it from a non-US entity, so they may not have any responsibility to give any of it back, because it was not being held by someone in the US [with rights in the US].

(note: IANAL)