The United States’ primary interest in the Middle East is regional stability. For now at least, constraints on U.S. power and the complex, interdependent nature of U.S. interests in the region—as well as the likelihood of sustained U.S.-Chinese rivalry that will inevitably divert U.S. strategic attention to the Asia-Pacific region—suggest that the best Middle East policy for Washington would be something closer to what international relations theorists call “offshore balancing”: refraining from engagement in overseas military operations and forgoing quasi-imperial nation building to focus instead on selectively using its considerable leverage to exert influence and protect U.S. interests. Washington needs to husband U.S. power in the Middle East, unless a genuine existential threat to its regional allies arises, which is unlikely. This course will require Washington to avoid any further projection of U.S. military power in the region—for example, a large-scale deployment of combat ground troops to fight ISIS.

Critics of U.S. restraint argue that in the absence of strongly asserted U.S. power, Iran or other U.S. nemeses will be emboldened—that restraint will lead to war. But U.S. adversaries will likely judge Washington’s resolve on the basis of conditions as they appear in the moment those adversaries are seriously considering aggressive actions, irrespective of conditions that existed years or months before. As long as the limits of U.S. restraint are clearly enunciated and Washington makes plain that its alliance with Israel remains undiminished, Iran will be loath to confront Israel or act much more aggressively in Iraq, Syria, Yemen, or elsewhere in the region for fear of triggering a decisive American response that could scupper the nuclear deal and revive the painful sanctions that drove Tehran to the bargaining table in the first place. In any case, the question of whether saber rattling will provoke or deter a potential adversary can never be answered with complete confidence, since decision-makers often misjudge the perceptions and temperament of their rivals.