Saudi Foreign Minister Saud al-Faisal with US Secretary of State John Kerry. (US State Department.)

Planning and leading a military coalition is a complex task, and Saudi efforts in Yemen are proving no exception.

Such interventions need a defined and achievable aim; simply relying on an air campaign to reinstate a political leader who remains resident in the country which is doing the bombing has its practical and political limitations. Such operations also need to take into account the likely short- and medium-term impacts of the intervention. Coalition partners need to understand (and, even better, agree with) the intent of the operation. And in the modern age there needs to be a great deal of attention paid to collateral damage.

On all those counts the Yemen intervention is posing some serious questions for Riyadh.

The US has provided support to the Saudis, in the shape of intelligence personnel and air-to-air refuelers, but there is a sense that this is more out of a desire to reaffirm the close relationship with Riyadh than out of any belief that Saudi action in Yemen is likely to resolve matters. Riyadh and Washington have not seen eye to eye on Syria, Iran or Iraq in recent years, so if limited support for Saudi Arabia's Yemen venture is what it takes to reinforce relations, then so be it. The concerns of some US military officers — that the Saudis have neither a coherent strategic aim or an ability to prosecute the tactical battle without inflicting significant civilian casualties — are expressed in this recent LA Times article.

There is a risk that, the longer the air campaign continues, the more that disparate elements of Yemeni society will see Saudi interference as the real enemy. And to reinforce the perception that Riyadh is paying insufficient attention to the second-order effects of its intervention, there are already indications that al Qaeda elements are taking advantage of the chaos by seizing the city of al-Mukalla.

Saudi Arabia is also finding that putting together a coalition is not a straightforward matter. Pakistan for instance, was originally listed as a coalition partner, but Islamabad has now declined the kind offer, drawing opprobrium from some quarters. And to top it off, Iraq's prime minister criticised Saudi actions in Yemen during a recent visit to Washington. Leading coalitions in the Middle East is no easy business, and it won't get any easier.