The Saudi-led Arab military intervention against the Iranian-backed Houthi coup in Yemen is a highly significant development, both in terms of the size of the coalition itself, as it comprises ten countries including Saudi Arabia, the UAE, Bahrain, Kuwait, Qatar, Egypt, Jordan, Morocco, Sudan, as well as Pakistan, and in terms of the swiftly-taken decision to launch Operation  Decisive Storm aimed at reinstating the legitimate government of President Abed Rabbo Mansour Hadi. Because Yemen's regional and international strategic importance, Western think tanks have showed considerable interest in the developments in several articles and reports on Operation Decisive Storm, presenting analyses and assessment of the coalition's capabilities, the nature of the ongoing military operation and the US position, as well as analyses of Yemen's crisis and the solutions proposed for achieving  stability and security in  the Middle East after the military operation.

Operation Decisive Storm: Legitimacy and fallout

Ibrahim Sharqieh, a Foreign Policy Fellow at the Brookings Institution and Deputy Director of the Brookings Doha Center, in a  recent analysis, says legitimacy of the Arab coalition's military intervention has been secured through:

• Two main regional organizations: the League of Arab States, and Organization for Islamic Cooperation (OIC), which expressed their unequivocal support to the Saudis;
• The elected Yemeni President Abed Rabbu Mansour Hadi's public request for Arab military intervention to restore security and stability to Yemen.
• The support shown by the  majority of Yemenis in Aden, Mareb, Taiz, Ibb and Hodeidah for the Arab intervention.

According to the writer, there had to be an Arab intervention because the Houthis' failed to respond to any calls to end their rebellion, rejected Saudi Arabia's call for negotiations in Riyadh and the U.N. invitations for peace talks in Doha, continued to take over several important cities and provinces through military force threatening regional security, forced the elected president out of the country and even alienated all Yemeni political parties— from Islamists to socialists— except a peculiar alliance with ousted President Ali Abdullah Saleh. It was the  Houthis' adamancy  that caused the failure of  all diplomatic efforts to reach a peaceful solution and made a military intervention inevitable to restore security and stability in Yemen. Given these circumstances, the Saudi-led Operation Decisive Storm in Yemen suggests a number of assumptions, according to Sharqieh.  

• First, coalitions emerging from within the region seem to hold much stronger and yield more tangible outcomes compared to international intervention, even when supported by Security Council resolutions.
• Second, regional coalition building reveals the limits of Iranian intervention in the Arab countries— or what Iranian leaders call a “control of the four capitals,”— Damascus, Baghdad, Beirut, and Sanaa. The writer says Iran will provide unlimited political, diplomatic, and to a certain extent arms support to the Houthis. However, it is unlikely Iran will fight a war on behalf of the Houthis in Yemen.
• Third, it is obvious that Saudi Arabia securing the firm support of major players like Egypt, Turkey, and Pakistan has sent powerful message to how far can Iran go with its support to the Houthis. Sharqieh says that this actually has led some political analysts in the region to suggest that a similar Turkey-led coalition could have put an end to the four year suffering of the Syrian people and that the solution is from within the region, away from international interventions.

Shape and duration of the military intervention

The nature and possible outcome of Operation Decisive Storm is a topic of interest for Western academics and think tanks. Michael Knights, a Boston-based Lafer International fellow of The Washington Institute, specializing in the military and security affairs of the Arabian Gulf states, says that although the shape and duration of Operation Decisive Storm is not yet known, the coalition is preparing to take steps in the three traditional spheres of modern warfare -- air, sea, and land:

• Airstrikes. In predawn attacks on March 26, Saudi strike aircraft bombed a range of military targets in Sanaa and the Houthi leadership center of Harf Sufyan in Amran governorate, including the house of Ansar Allah leader Abdul Majid al-Houthi. Strikes continued throughout the day involving Emirati, Jordanian, Kuwaiti, Bahraini, and Qatari air forces. In theory, around 170 modern strike aircraft have been allocated to the effort, including 100 from Saudi Arabia (mostly F-15S and Tornado IDS aircraft), 30 from the UAE (F-16s and Mirage 2000s), and several F-16s from Bahrain (15), Jordan (6), and Morocco (6). If needed, Riyadh could easily commit far larger numbers; Egypt and Pakistan could contribute aircraft as well.
• Naval operations. Cairo and Riyadh have already committed naval and coast guard forces to the operation, with Egyptian craft patrolling the Bab al-Mandab Strait and Saudi vessels extending their preexisting coastal patrols off Yemen to include Red Sea ports used for military resupply by the Houthis. Pakistan may provide naval assets as well. Egypt, Saudi Arabia, and the UAE also have the ability to mount amphibious operations along Yemen's coast, threatening the western flank of the Houthi advance.
• Land operations. Saudi Arabia is mobilizing land forces along its southern border with Yemen, the same terrain over which it fought the Houthis in 2009-2010. In Aden, where pro-government forces are fighting to hold the airport and other key installations, Riyadh, Cairo, and Pakistan also appear to be preparing for the option of landing small expeditionary forces. Other pockets are holding out against Houthi-allied forces in the oil-rich Mareb governorate and the natural gas center of Shabwa, though tribal forces in these areas seem to be leaning as much on military support from al-Qaeda in the Arabian Peninsula (AQAP) as from pro-government security forces.

US position on Yemen and limits of its role 

At Western-based think tanks, most analysis of the developments of Yemen conflict is focused on the US position, on the one hand, and the efficiency of the US-Saudi partnership, on the other. Anthony H. Cordesman, a senior strategic analyst and expert on Middle Eastern security at the Washington-based Center for Strategic and International Studies (CSIS), explains that Yemen is a growing reminder of just how important the strategic U.S. partnership with Saudi Arabia really is, particularly in terms of oil and energy, as the U.S. remains dependent on supplies from the Arabian Gulf states through the Strait of Hormuz.

For Cordesman, the flow of oil and gas tanker traffic out of the Gulf and through the Strait of Hormuz remains the West's most important energy chokepoint. The United States is finding out that calling for strategic partnership is not a way of avoiding its role as a world power. The senior expert notes that the U.S. has already said it would give logistical and intelligence support, but the situation in Yemen may well come to require more than that, and some kind of U.S. combat support as well as U.S. diplomatic pressure on Iran.  In this context, TWI's  Michael Knights noted the United States is an unspoken member of the Saudi-led coalition, operating "a joint planning cell with Saudi Arabia to coordinate U.S. military and intelligence support," in the words of National Security Council spokeswoman Bernadette Meehan. (Editor: Saudi  Arabia has not stated or even implied this). Knights noted that the United States needs to balance carefully the complexities of the current situation and set triggers for further U.S. involvement on certain issues.

For instance, Al-Qaeda in the Arabian Peninsula (AQAP) will likely use the conflict in Yemen to slip further into the political-military mainstream, much as some Salafi militant groups have done in Syria since the uprising against Bashar al-Assad began. The "Islamic State"/ISIS is likewise trying to grow in the chaos and vacuum of faltering state authority. The Obama administration should reinforce Arab caution toward such groups and resist their integration into any anti-Houthi coalition on the ground in Yemen, maintaining as much continuity as possible in the U.S.-led counter-terrorism mission.

What is next after Operation Decisive Storm?

Western experts shows great interest in the next stage after Operation Decisive Storm is over, particularly as Saudi Arabia lacks powerful allies on the ground in Yemen. Most Western views express concern over the consequences of this military operation on Yemen’s future, if no alternative political plan (Plan B) is put in place for the post-intervention stage.

Frederic Wehrey, Senior Associate in the Middle East Program at the Carnegie Endowment for International Peace, explains that pro-Saudi factions, such as the tribal militias of the powerful al-Ahmar family, various Salafi groups, and the government of ousted president Hadi, have all been decisively beaten by the Houthis since their southward advance began in earnest in mid-2014. Stressing that the net effect of this operation is ultimately dangerous for Yemen’s future path, Wehrey expects that it will open up more fissures on the ground, perhaps bolster the Houthis’ popular support as defenders of Yemeni sovereignty, and create more opportunities for AQAP and the Islamic State to flourish.

He even stressed that airstrikes without corresponding ground forces do not produce decisive victories. In the same context, Simon Henderson, the Baker Fellow at The Washington Institute and Director of the Institute's Gulf and Energy Policy Program, specializing in energy matters, warns  that a failure of Operation Decisive Storm will carry big risks and  will be at best embarrassing for Saudi Arabia and the coalition members, because  none of these states appear to have a “Plan B” if Hadi cannot be put back in his presidential palace.

Some experts, including Sharqieh and Wehrey, proposed the following solutions for the post-military intervention stage:

• Talking to  Iran is necessary to  ensure sustainability of any solutions that are reached.
• Yemeni parties should negotiate on an equal footing and the Houthis should be allowed to negotiate with dignity. They should be partners in rebuilding Yemen, not controlling and excluding others.
• Saudi-led coalition should be very careful not to destroy state institutions in the process of removing the Houthis from power. Destroying institutions will likely lead to protracted instability; Libya is a clear example of this.
• Saudi-led coalition should engage with those brigades of the Yemeni army loyal to Saleh, as some probably pledged allegiance to him in the absence of better alternatives. One of the mistakes in the 2011 GCC imitative was allowing Saleh to remain an active player in Yemeni politics. This could be an opportunity to correct that mistake, and ensure that the time has come for him to retire.
• Yemenis’ welcome of military intervention should not be taken for granted. For historical reasons, Yemenis in general are sensitive to external interventions in their affairs and also to Saudi relations with various players in the Yemeni political scene. Riyadh therefore should reassure Yemenis that their intervention is not going to replace Houthi control with Saudi guardianship.
• Riyadh's possible reconsideration of its relation with political Islam including,  the Muslim Brotherhood’s Al-Islah party in Yemen, in order to bolster its influence on the ground in Yemen and create a force to counter the Houthi rebels.

Sources:

Ibrahim Sharqieh, Will Saudi Arabia's 'Operation Decisive Storm restore order in Yemen? (Washington, Brookings Institution, 27 March 2015).

Michael Knights, Assisting the Arab Military Intervention in Yemen (Washington, The Washington Institute for Near East Policy, 27 March 2015).

Anthony H. Cordesman, America, Saudi Arabia, and the Strategic Importance of Yemen (Washington, The Center for Strategic and International Studies "CSIS", 26 March 2015).

Frederic Wehrey, Into the Maelstrom: The Saudi-Led Misadventure in Yemen (Washington, Carnegie Endowment for International peace, 26 March 2015).

Simon Henderson, Saudi Arabia's Big Gamble (Washington, The Washington Institute for Near East Policy, 26 March 2015).