U.S.-SAUDI-IRAN RIVALRY

This rivalry will likely eclipse other Middle Eastern fault lines in 2018. It is enabled and exacerbated by three parallel developments: the consolidation of the authority of Mohammed bin Salman, Saudi Arabia’s assertive crown prince; the Trump administration’s more aggressive strategy toward Iran; and the end of the Islamic State’s territorial control in Iraq and Syria, which allows Washington and Riyadh to aim the spotlight more firmly on Iran.

The contours of a U.S./Saudi strategy (with an important Israeli assist) are becoming clear. It is based on an overriding assumption that Iran has exploited passive regional and international actors to bolster its position in Syria, Iraq, Yemen, and Lebanon. Washington and Riyadh seek to re-establish a sense of deterrence by convincing Tehran that it will pay at least as high a price for its actions as it can inflict on its adversaries.

The strategy seems to involve multiple forms of pressure to contain, squeeze, exhaust, and ultimately push back Iran. It has an economic dimension (via U.S. sanctions); a diplomatic one (witness vocal U.S. and Saudi denunciations of Iran’s regional behavior and Riyadh’s ham-handed attempt to force Lebanese Prime Minister Saad Hariri’s resignation); and a military one (so far exerted principally by Saudi Arabia in Yemen and by Israel in Syria).

Whether it will work is another question. Although recent protests in Iran have introduced a new and unpredictable variable, Tehran and its partners still appear to be in a strong position. The Bashar al-Assad regime, backed by Russian air power, is prevailing in Syria. Across Iraq, Iran-linked Shiite militias are entrenching themselves in state institutions. In Yemen, Tehran’s relatively small investment in backing the Houthis has helped them weather the Saudi-led campaign and even launch missiles of unprecedented range and accuracy into Saudi territory.

Despite demonstrating its resolve to confront Iran and its partners, Riyadh has been unable to alter the balance of power. Forcing Hariri’s resignation backfired, not just because he later withdrew it, but also because all of Lebanon united against the move and Hariri then inched closer to Lebanese President Michel Aoun and Hezbollah. In Yemen, Riyadh turned the Houthis and former President Ali Abdullah Saleh against each other, but in doing so further fragmented the country and complicated the search for a settlement and a face-saving Saudi exit from a war that is enormously costly not only to Yemenis but also to Riyadh’s international standing. The Trump administration confronts similar obstacles. Thus far its belligerence, refusal to certify the nuclear deal, threats of new sanctions, and launching of several strikes at and near regime targets in Syria have done little to reverse Tehran’s reach.

With so many flashpoints, and so little diplomacy, the risk of an escalatory cycle is great: Any move — new U.S. sanctions that Iran would see as violating the nuclear deal; a Houthi missile strike hitting Riyadh or Abu Dhabi, for which Washington and Riyadh would hold Tehran responsible; or an Israeli strike in Syria that kills Iranians — could trigger a broader confrontation.

A Rohingya refugee boy desperate for aid cries as he climbs on a truck distributing aid for a local NGO near the Balukali refugee camp on Sept. 20, in Cox’s Bazar, Bangladesh. (Kevin Frayer/Getty Images)