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.