The New Year's execution by Saudi Arabia of the Shiite cleric Sheikh Nimr Baqir al-Nimr was a deliberate provocation.
Its first purpose: Signal the new ruthlessness and resolve of the Saudi monarchy where the power behind the throne is the octogenarian King Salman's son, the 30-year-old Defense Minister Mohammed bin Salman.
Second, crystallize, widen and deepen a national-religious divide between Sunni and Shiite, Arab and Persian, Riyadh and Tehran.
Third, rupture the rapprochement between Iran and the United States and abort the Iranian nuclear deal.
The provocation succeeded in its near-term goal. An Iranian mob gutted and burned the Saudi embassy, causing diplomats to flee, and Riyadh to sever diplomatic ties.
From Baghdad to Bahrain, Shiites protested the execution of a cleric who, while a severe critic of Saudi despotism and a champion of Shiite rights, was not convicted of inciting revolution or terror.
In America, the reaction has been divided.
The Wall Street Journal rushed, sword in hand, to the side of the Saudi royals: "The U.S. should make clear to Iran and Russia that it will defend the Kingdom from Iranian attempts to destabilize or invade."
The Washington Post was disgusted. In an editorial, "A Reckless Regime," it called the execution risky, ruthless and unjustified.
Yet there is a lesson here.
Like every regime in the Middle East, the Saudis look out for their own national interests first. And their goals here are to first force us to choose between them and Iran, and then to conscript U.S. power on their side in the coming wars of the Middle East.
Thus the Saudis went AWOL from the battle against ISIS and al-Qaida in Iraq and Syria. Yet they persuaded us to help them crush the Houthi rebels in Yemen, though the Houthis never attacked us and would have exterminated al-Qaida.
Now that a Saudi coalition has driven the Houthis back toward their northern basecamp, ISIS and al-Qaida have moved into some of the vacated terrain. What kind of victory is that -- for us?
In the economic realm, also, the Saudis are doing us no favors.
While Riyadh is keeping up oil production and steadily bringing down the world price on which Iranian and Russian prosperity hangs, the Saudis are also crippling the U.S. fracking industry they fear.
The Turks, too, look out for number one. The Turkish shoot-down of that Russian fighter-bomber, which may have intruded into its airspace for 17 seconds, was both a case in point and a dangerous and provocative act.
Had Vladimir Putin chosen to respond militarily against Turkey, a NATO ally, his justified retaliation could have produced demands from Ankara for the United States to come to its defense against Russia.
A military clash with our former Cold War adversary, which half a dozen U.S. presidents skillfully avoided, might well have been at hand.
These incidents raise some long-dormant but overdue questions.
What exactly is our vital interest in a permanent military alliance that obligates us to go to war on behalf of an autocratic ally as erratic and rash as Turkey's Tayyip Recep Erdogan?
Do U.S.-Turkish interests really coincide today?
While Turkey's half-million-man army could easily seal the Syrian border and keep ISIS fighters from entering or leaving, it has failed to do so. Instead, Turkey is using its army to crush the Kurdish PKK and threaten the Syrian Kurds who are helping us battle ISIS.
In Syria's civil war -- with the army of Bashar Assad battling ISIS and al-Qaida -- it is Russia and Iran and even Hezbollah that seem to be more allies of the moment than the Turks, Saudis or Gulf Arabs.
"We have no permanent allies ... no permanent enemies ... only permanent interests" is a loose translation of the dictum of the 19th century British Prime Minister Lord Palmerston.
Turkey's shoot-down of a Russian jet and the Saudi execution of a revered Shiite cleric, who threatened no one in prison, should cause the United States to undertake a cost-benefit analysis of the alliances and war guarantees we have outstanding, many of them dating back half a century.
Do all, do any, still serve U.S. vital national interests?
In the Middle East, where the crucial Western interest is oil, and every nation -- Saudi Arabia, Iran, Iraq, Libya -- has to sell it to survive -- no nation should be able drag us into a war not of our own choosing.
In cases where we share a common enemy, we should follow the wise counsel of the Founding Fathers and entrust our security, if need be, to "temporary," but not "permanent" or "entangling alliances."
Moreover, given the myriad religious, national and tribal divisions between the nations of the Middle East, and within many of them, we should continue in the footsteps of our fathers, who kept us out of such wars when they bedeviled the European continent of the 19th century.
This hubristic Saudi blunder should be a wake-up call for us all.