Nobody knows what to do. Bring on Armegeddon! seems to be the main plan, but that would be a bad idea and not a permanent solution even if it would pay off some karma.
Take Iran. You tell them their nuclear activities shall cease tomorrow or not one drop of oil will leave an Iranian terminal and reach any overseas destination. They won't believe you, so you seize a full supertanker, keep the oil and auction off the vessel itself, previous owners be damned. They will howl. Let them howl. Then do it again.
If they want to escalate to taking on the USN in the gulf, let them. They didn't decide to do so yesterday, so they probably don't actually relish the prospect. But if they try it, sink them all. And promise to do it again.
Or take North Korea. It has been caught out giving nukes to Syria and lying to us about it, after accepting renewed payments and concessions to "come clean", and failing to do so. So you tell them their banking allowed deal is off. Not only do they not have access to banks, but the US will observe a secondary boycott against anyone who banks with them. It is an anti counterfeiting measure, and anyone who doesn't play is a money laundering criminal and all their assets may be seized, anywhere.
Russia and China steal our software and then try to overcharge us for oil in the former case, or manage currencies in the latter case. OK fine, so the price of entry for any of their goods to the US just went up, by the total cost of all lost software sales to piracy, ever, tripled. Prorate it over their trade. If they don't want to pay it they can lose access to the US market permanently.
Oh, and until the spam flood stops, all internet and telephonic connections to them from the US are severed. Oh, and until they stop supporting terrorist regimes, we can't trust those given their passports, so none of their nationals can enter the US for any reason.
No one is willing to make the bastards pay the slightest price for their ridiculous testing behavior. Simple make them pay a price, make it steep, and the more they howl, the steeper it goes. You don't ask permission, you don't link it directly to the offense. It is simply non-specific "we don't like what you are up to", deliberate crossing retaliation.
The US has acres of soft power and plenty of the hard to back it up. But no one will use it, because we have no will, we are paralyzed PC pussycats. It is ridiculous and it is obscene, and it will end in blood and terror.