Editorial: Mali's lesson is that we still need the US

French and Mali government forces were on the point of taking back the city of Timbuktu from Islamist insurgents yesterday. The city's history, its resonant name and its strategic position all make its liberation the symbol of overall victory. France, which had promised a short, sharp intervention at the request of the beleaguered Mali government, will be able to claim success, and leave. With the French will go the limited assistance that Britain has given its ally: two transport planes; intelligence and logistical support; perhaps some special forces.

Yet there is a risk that everyone, the French included, may be getting ahead of themselves here. It is not at all certain that the Mali government could have survived in power, let alone taken back the state's north-eastern territory, without help, and the insurgents seem less to have been defeated than to have melted away. Without the French prop, the Mali government – and its army, which hardly distinguished itself in the fight – looks a shaky proposition. It is doubtful, too, whether the African force that is supposed to replace them can or will do so.

And if France is to prolong its involvement, what then? To be sure, ministers will face questions at home, from those fearful of the eventual bill. But the operation has already exposed serious gaps in France's military capability. Britain loaned the troop carriers, not just out of solidarity but because France did not have enough. Paris had to ask a reluctant Washington for help with capacity for mid-air refuelling, which France does not possess.

As with the Libya operation two years ago, it is clear that France and Britain between them cannot mount even such limited operations entirely by themselves. They need the sort of support from the US that the Obama administration has been reluctant to give. It might be argued that this may wake Europe up to the need for more and better co-ordinated military spending. But that is a long-term prescription, and the problem of Islamist insurgency in Saharan Africa looks ever more pressing.