President Donald Trump\u2019s withdrawal from the Iran nuclear deal didn\u2019t draw much international applause, but three US allies in the Middle East\u2014Israel, Saudi Arabia and the United Arab Emirates\u2014warmly welcomed the move. Israel had long said that the deal didn\u2019t do enough to prevent Iran from becoming a nuclear power, and Gulf Arab countries believed it gave Iran cover for an intensified campaign of destabilising the Arab world. They have plenty of ideas when it comes to drawing up a plan B for a U.S.-led containment campaign against Iran. Saudi Arabia and the UAE never shared President Barack Obama\u2019s conviction that engagement and sanctions relief could moderate Iran\u2019s revolutionary brashness, regional meddling, and support for sectarian extremists. So, they\u2019re pleased by Trump\u2019s rhetorical attacks and re-imposed sanctions against the Iranian regime, and they want the U.S. to foreclose any efforts by European countries, that remain signatories to the nuclear deal, to find a way to let their companies keep doing business with Iranian institutions. However, Iran\u2019s expansion as a regional power largely took place before the nuclear deal was signed, and the comprehensive international sanctions that existed in the years leading up to the agreement did not deter Tehran\u2019s support for extremist groups in Arab countries like Iraq, Syria, Lebanon, Bahrain and Yemen. So the Gulf states don\u2019t expect sanctions alone to do the trick. They hope that with the Islamic State crushed in Iraq and Syria, Washington will now lead a coordinated regional strategy to cut Iran\u2019s power down to size. Among other things, they want limited and focused military action to reverse some of the gains Iran has made since the U.S. invasion of Iraq in 2003. Indeed, they\u2019ve already taken on the Iranian-backed Houthi rebels in Yemen, as well as the local al-Qaeda affiliate. They may also hope to play a role in confronting Iran\u2019s lawless behaviour in the waters of the Gulf itself. They are looking for Washington to take the lead in confronting Iran in Iraq, but there, too, Saudi Arabia has shown it is willing to play a diplomatic, political and financial role. Perhaps, the most strategically vital theatre in any such campaign would be Syria, which is far from the Gulf countries. There, they hope that Israel will enforce its own red lines on Iranian conduct and make life difficult for the Hezbollah militants in Syria, and possibly, even in their home base of Lebanon. They would urge the U.S. to prevent Iran from taking advantage of the collapse of the Islamic State in western Iraq and eastern Syria in order to create a secured military corridor running from Iran to Lebanon and the Mediterranean. Such a strategic upheaval, if secured and consolidated, would ensure that Iran emerges as a regional superpower. Gulf Arab countries also want to work with the U.S. to persuade Turkey and Russia that their interests in Syria are not served by an empowered and aggressive Iran. Otherwise, Russia could prove a major obstacle to reducing Iran\u2019s influence in Syria and getting Hezbollah to go back to Lebanon. Finally, while the Gulf countries don\u2019t want an all-out war with Iran, there are signs of Arab and American encouragement of uprisings by Iranian ethnic minorities, such as the Baluchis, Arabs and the Kurds. The goal isn\u2019t regime change, partly because that\u2019s not considered a serious possibility at the moment. What they want, instead, is a sustained containment campaign to pressure Iran to change its behaviour and ambitions, and constrain its ability to destabilise neighbours and spread influence. It\u2019s a big ask, and probably bigger than many Gulf Arab leaders realise. After decades of U.S. leadership in the region, these countries grew used to, and benefited from, a U.S.-enforced regional order. But now, especially after Iraq and Afghanistan, Americans across the political spectrum have an advanced case of Middle East war fatigue. Trump\u2019s \u201cAmerica First\u201d campaign didn\u2019t signal much enthusiasm for the kind of interventionist foreign policy that these Gulf allies are hoping for. But, if the U.S. wants to combat terrorism and confront Iran, as the administration insists it does, Trump\u2019s idea of withdrawing the more than 2,000 U.S. forces in Syria is a non-starter. The Gulf countries aren\u2019t asking for a repetition of the 2003 adventure in Iraq, which they didn\u2019t support or encourage. What they want is a multi-front effort to roll back Iran\u2019s influence by de-fanging its proxies, supporting its enemies and insurgents, and choking off its economy. Only Washington, they believe, can do that. The idea is especially to weaken Iran\u2019s Revolutionary Guards and its clients around the region. Containing Iran will take time, effort, and troops, and will not be painless. But, it needn\u2019t and shouldn\u2019t be a madcap adventure like the campaign that began in 2003 to remake Iraq in an American image. Instead, as Russia has demonstrated in Syria, even in the Middle East, it\u2019s possible to secure limited goals with limited means, especially if allies work together. That\u2019s what Saudi Arabia and the UAE are hoping is in the works for a plan B regarding Iran. By Hussein Ibish.Senior resident scholar at the Arab Gulf States Institute, Washington. This column doesn\u2019t necessarily reflect the opinion of the editorial board, or Bloomberg LP and its owners.