The US should conduct a military strike in response to the Iranian attack on the Abqaiq oil facility in Saudi Arabia in order to deter continued Iranian military escalation. Deterrence requires more than punitive strikes. It requires credibly holding at risk something the regime is not willing to lose. Beginning an air campaign against Islamic Revolutionary Guards Corps (IRGC) targets in Syria is one approach; a significant air and missile campaign against targets in Iran itself is another. Each option carries its own significant risks and opportunities, which must be weighed carefully before choosing a course of action. The risks of any retaliatory strike are high, but the risks of failing to respond to the Abqaiq attack are higher.

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The attack on Abqaiq was planned and executed by Iran and most likely launched from Iranian territory. It was part of a pattern of Iranian military escalation in response to the Trump administration’s “maximum pressure” campaign.

The al Houthi’s claim to have conducted the attack was part of a skillful information operation intended to divert the Western discussion away from Iran’s role and focus it instead on the war in Yemen and on Saudi Arabia’s misdeeds. That information operation has succeeded to a considerable extent, as the Western debate has indeed focused excessively on the question of attributing the attack, on Saudi Arabia’s culpability for the humanitarian situation and its own bombing campaign in Yemen, and on the horrific murder and dismemberment of Jamal Khashoggi.

The US and Iran are escalating in parallel. The US has steadily increased sanctions and other economic pressure, has deployed limited military forces to the region to bolster its allies’ defenses and its own, and has formed a maritime defensive operation to deter Iranian seizures of oil tankers. Iran and its allies and proxies have escalated military attacks, including shooting at (and shooting down) multiple American drones, firing rockets and mortars at US positions in Iraq, and repeatedly attacking Saudi oil infrastructure and a desalination plant. It has also escalated its violations of the nuclear deal. Increasing American economic pressure has not deterred Iranian military or nuclear deal–violation escalation, and American military actions have only changed the precise shape of Iranian military escalation, if that. The US has not therefore identified a nonviolent means of deterring future Iranian escalation.

View the interactive timeline of recent US-Iran escalation.

One of Iran’s central objectives in the Abqaiq attack was separating the US from its partners in the Gulf, particularly Saudi Arabia and the United Arab Emirates. The Iranians likely chose this escalation step over others because it hit Saudi Arabia alone and thereby forced the US to choose explicitly whether it would defend a front-line state exposed by the “maximum pressure” campaign. American inaction, which includes encouraging the Saudis to conduct a military retaliation of their own, will further this Iranian objective by solidifying the belief in Riyadh and Abu Dhabi that the US will not defend front-line states even against serious Iranian military attack.

The US has vital economic interests in defending Saudi (and more generally Gulf) oil infrastructure even though America imports little Gulf oil. Oil is a fungible commodity, and its global price rises and falls depending on global supply and demand. Americans will pay higher prices for petroleum products if large amounts of Saudi oil remain off the market, regardless of America’s technical “independence” of Saudi oil, because the global price will rise. Additionally, America’s allies that do depend on Saudi oil could be economically devastated by a protracted disruption in Saudi oil exports. Such damage to vital American trading partners would severely damage the American economy as well.

Furthermore, reducing the “maximum pressure” campaign or seeking negotiations with Iran without military retaliation will establish the global precedent that America and the West will surrender to military attacks, thereby increasing the likelihood of future military attacks by Iran or other adversaries. The US must first demonstrate a willingness to respond to unjustified aggression and attacks on its allies before considering any significant change in its overall policies toward Iran.

Deterrence requires holding at risk something that the adversary is unwilling to lose and that the US might plausibly take away. Using military force simply to indicate US strength or displeasure will not deter a determined adversary.

It is difficult to identify Iranian target sets that would deter the regime without also moving toward a military regime-change operation, which is unwise and likely impracticable. For example, limited American military strikes against the positions from which the Abqaiq attack were launched will not likely meet the necessary deterrence threshold given the existential nature of the threat maximum pressure poses to the Iranian regime. The US cannot—and should not— plausibly aim at overthrowing the Islamic Republic by military means, which means attacking targets in Iran is not likely to deter Iran.

Iranian leaders have frequently identified Iran’s positions in Syria as vital to the regime’s survival. Those positions are far more vulnerable to American attack than the Iranian regime is at home. The threat of American action against IRGC positions in Syria is also more credible than the threat of a massive military regime-change operation in Iran. Therefore, presenting Tehran with the choice of continuing its military escalation or seeing its positions in Syria severely degraded is the best chance the US has to deter continued Iranian military action.

The risks of such an attack include Iranian military escalation. Iran could attack Americans in Syria, Iraq, or elsewhere in the Gulf region; it could conduct terrorist attacks in the US itself or in allied states in Europe or Latin America; it could interfere with the movement of ships through the Strait of Hormuz; or it could attack more vital targets in Saudi Arabia and the United Arab Emirates. The US and its allies can mitigate these threats to varying degrees, but never completely. We must recognize, however, that Iran is on a military escalation path and may well decide to conduct such actions even if the US makes no response to the Abqaiq attack. On the contrary, trends suggest that inaction may encourage further Iranian escalation.

American military action against Iran in Syria could also have severe diplomatic repercussions. It could persuade European leaders to support the Assad government up to and including recognizing it. Turkey’s response to such an operation is unclear. The US would have to work energetically to minimize the likelihood of these and other negative diplomatic consequences of any action in Syria, recognizing that it might not be able to do so fully.

The Russians could also use their advanced air defense systems in Syria against US aircraft and missiles attacking Iranian targets. The US could mitigate that risk by deploying the force package necessary to defeat those systems and prevent the Russians from replacing or reinforcing them. A detailed assessment of Vladimir Putin’s objectives and constraints in Syria strongly suggests that he is unlikely to engage in such a direct conflict, particularly if American strikes avoid hitting Russian targets. The notion that he would initiate a global thermonuclear war over a local conflict in Syria is absurd.

Despite the risks of military action, military inaction may in fact be more dangerous. The Iranians are on a path to split the Saudis and Emiratis from the US. Success in that endeavor would unravel the “maximum pressure” campaign that relies on those states to adhere to financial and other sanctions and provide military support to American objectives in the region. It would create opportunities for both Russia and China to gain firm footholds in the Gulf, transforming the regional security challenge facing the US.

Inaction would also strengthen the convictions of Iran’s leaders that they can conduct large-scale devastating attacks against American allies at will, particularly if they do not kill Americans. It will therefore likely accelerate the very escalation scenarios frequently offered as arguments against an American retaliatory strike.

Inaction harms every American alliance by undermining US allies’ belief that America will come to their aid militarily if they are attacked. Rhetorical dances around the lack of a formal American security guarantee to Saudi Arabia will not affect this fear, nor will reassurances that the US would defend this or that other ally. All such rhetoric will be undermined by American inaction in this case and the much louder rhetoric from the White House about the need for other states to defend themselves.

There is no safe course the US can pursue after Abqaiq. Both action and inaction carry great risks. The balance of risk at the moment lies with inaction; failure to respond militarily to the Abqaiq attack is far more likely to harm American security and vital national interests, including economic interests, than is prudent action.

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