Democracy or monarchy doesn't matter in this case, because US has no gold at all. That's a real reason why they are not allowing germans to inspect their gold, for example.
If I were to theorise they probably keep it in ratios like with fractional reserve banking in their own system, so they piss around with it in the back when the countries aren't looking and keep a certain amount just in case people get suspicious like the Dutch are, if they haven't given it to the Germans then that probably means they've messed with the German gold and can't get it back.