The weekend attack on oil facilities in Saudi Arabia, which Secretary of State Mike Pompeo blamed on Iran Wednesday and called an “act of war,” shows that the Obama administration was delusional to think the 2015 nuclear deal with Iran would curb that nation’s radical and violent policies.

Iran has repeatedly intervened abroad directly and through surrogates and continued its intercontinental ballistic missile program regardless of the nuclear deal, which is officially called the Joint Comprehensive Plan of Action.

All indications from U.S. and Saudi officials are that that the sophisticated drones and missiles involved in the attack on Saudi Arabia were launched from Iran.

SAUDI OIL ATTACKS AN 'ACT OF WAR' BY IRAN, NOT YEMEN REBELS, POMPEO CLAIMS

An appropriate response should be directed not only at the Iranian-backed Houthi rebels in Yemen who have claimed responsibility for the attack, but also at Iran if its involvement in the attack is firmly established.

Iran should not be allowed to continue to exploit an apparent immunity from accountability because it typically uses surrogate forces and territory to attack its enemies.

The 2015 nuclear deal reached with the U.S. and other nations did absolutely nothing to stop the Islamic Republic from using surrogates, and now from more direct involvement in an attack on Saudi Arabia, if Pompeo’s assessment is correct.

Asked if Iran was responsible for the attack on Saudi Arabia, President Trump said that “it’s looking that way.” The president said an investigation was underway and that he wanted to “avoid” war, but was leaving all options open.

President Trump tweeted Wednesday that he “instructed the Secretary of the Treasury to substantially increase Sanctions on the country of Iran!” That’s a good move, but won’t end Iran’s support of terrorist groups and its own aggressive behavior.

The call for increased sanctions makes clear the president is unprepared to renew U.S. participation in the Iran nuclear deal. That is a sound decision, since Iran understands that deal as immunizing it from sanctions brought on by its disregard of international rules, so long as it adheres to its nuclear promises.

Accepting the nuclear deal on that premise would accept the untenable understanding that it limits Iran’s obligations to a temporary, partial suspension of its nuclear program – while implicitly accepting and funding Iran’s other dangerous activities through the release of some $125 billion in frozen Iranian assets and another $1.5 billion in U.S. cash.

No deal that allowed Iran to assume it was free to continue to violate fundamental sovereign obligations could possibly endure.

The U.S. had tried a milder version of wishful thinking in the Algiers Accords in 1981. Iran returned our diplomats held hostage and we unfroze its U.S. assets and lifted all sanctions. Then too, Iran understood the U.S. government to have accepted a new normal in which Iran could pursue its radical agenda with impunity.

Inevitably, Iranian murders abroad and Revolutionary Guard Corps missiles and mines in the Persian Gulf led the U.S. to again impose sanctions. The nuclear deal is far less defensible than the Algiers Accords in that it lacked legitimacy. It was neither a treaty, nor an executive agreement, nor a commitment approved by domestic law. It never gained majority support in Congress.

But sanctions alone will not demonstrate strength adequate to deter Iran. The U.S. must adopt other measures necessary to achieve that objective.

We failed to do so in response to Iran’s role in the bombing of the Khobar Towers in Saudi Arabia (killing 19 U.S. airmen and wounding hundreds); or in supplying armor-penetrating weapons to Iran’s Shiite allies in Iraq (enabling them to kill hundreds of Americans); or most recently when Iran shot down a U.S. drone.

Covert measures – such as the Stuxnet computer virus deployed against Iran – can have positive effects; but avowed actions convey clearer messages.

So, what more should the U.S. do now beyond the unspecified sanctions announced by President Trump?

The U.S. knows how to demonstrate proportionate but responsible strength, as it did in negotiating with the Soviets. With Iran, American presidents of both parties have since 1979 negotiated from weakness, relying on empty threats and amateurish initiatives.

Strength need not mean war. But adequate strength to deter a radical agenda is as necessary and potentially effective in dealing with Iran as it was in dealing with the Soviets.

During Operation Praying Mantis in 1988, the U.S. hit several gunboats, warships and planes belonging to the Iranian Revolutionary Guard Corps. The Revolutionary Guards have never again fired missiles at U.S. flagged vessels or laid mines in the Gulf.

Similarly, after President George H.W. Bush pushed Iraq out of Kuwait, Iranian President Hashemi Rafsanjani arranged to release the hostages held in Lebanon. After President George W. Bush attacked Al Qaeda in Afghanistan, Iran cooperated in establishing a new government. And after the U.S. drove President Saddam Hussein from power in Iraq, Iran offered to negotiate with the U.S. on all issues.

As strength, including sanctions, has its impact, the U.S. will have diplomatic options which we should seriously pursue. Negotiating with Iran makes sense, just as negotiating with the Soviet Union did despite its being what President Ronald Reagan called an “Evil Empire.”

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We had opportunities after Praying Mantis and the Afghanistan and Iraqi actions to negotiate, but failed to respond positively. Today direct negotiations with Iran are unlikely. But firmness and creative initiatives could enable the leaders of both nations to engage.

What possible diplomatic steps could be taken?

Once diplomacy becomes feasible, a viable approach could be a process of “conscious parallelism” by which both the U.S. and Iran would take steps towards a better relationship that the other nation would view positively and respond to with comparable steps.

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Working with other nations that were part of the Iran nuclear deal in this process could give the U.S. greater leverage, and an acceptable channel for reciprocal arrangements.

Any such effort would require climbing down from rhetorical confrontation, which may be impossible in today’s political climate. But the pressure for progress grows. And U.S. diplomacy is currently full of surprises. President Trump is wise not to rush into military action. But he cannot succeed if he continues to ignore Iran’s ever-worsening behavior.