Apart from the apologists for the Obama administration's nuclear deal with Iran, all objective observers agree that the Iranian economy is being crushed by U.S.-imposed sanctions.  But due to a combination of pride and religious fanaticism, the Iranian regime refuses to abandon its terroristic ways or to walk away from its ambition to possess nuclear weapons.

Being strangled by the U.S. sanctions, the mullah's ideal strategy could be summed up as follows: "If we can ship our oil, we'll see to it that nobody else can."  But of course Iran lacks the ability to shut down oil exports from the Gulf.  And if they even tried, the Iranians would invite a level of destruction on themselves that could collapse the regime or at the very least take many years to recover from.

So as an alternate strategy, Iran resorts to pinprick harassments — attacking a few oil tankers, capturing some others.  The goal here is to cause disruption in the energy markets and prompt Europe and others to pressure the United states to return to the Obama nuclear deal.

But this harassment strategy is delicate.  It has to be significant enough to achieve its objective, yet not breach the threshold that would result in a no-nonsense response.  With its attack, either by itself directly or through its surrogates, on the Saudi oil-production facilities, Iran may have crossed that threshold.

The payback for this brazen attack does not have to be extracted immediately or even directly.  To date, Iran has played the low-cost asymmetric warfare game to its advantage.  But there's no reason why its enemies can't turn the table and return the favor.  In this regard, Iran is highly vulnerable.

The drop in Iranian oil export revenues already has the Iranian economy reeling with high unemployment and inflation.  Now President Trump is increasing the sanctions.  America can to more do cripple Iran, but it doesn't have to.

More than 90 percent of Iran's oil exports flow from a single point: Kharg Island.  A single sortie would be more than enough to simply eliminate Iran from global oil markets.  And because Kharg Island lacks a bridge to mainland Iran, Iran would find it impossible to restart its exports without American approval.

Another point of vulnerability is the port of Bandar Abbas.  That's where three quarters of Iranian imports come into.  Both Bandar Abbas and Kharg Island are choke points.  The U.S. Navy could shut down both ports in an afternoon.  But that's not needed.  Virtually any enemy of Iran can use a swarm of drones, as Iran did to the Saudis, to severely damage Bandar Abbas and Kharg Island or shut them down with a cyber-attack.

The point is that to date, the Iranians have had a free hand in playing offense in the Middle East — in Syria, Iraq, Lebanon, and the Gulf waters.  There is no law of nature prohibiting others to do the same to Iran.  This is not to say it will happen — only that it easily could.  If the mullahs want to play with fire, they should not complain when they get burned.