Thursday’s operation by 4,000 US marines in southern Helmand marks the start of a critical new phase in America’s Afghan strategy. For years, western leaders have feared that Nato is losing the fight against the Taliban, that the US-led operation is under-resourced, that President Hamid Karzai’s government is too weak. Now, hopefully, things are about to change. Barack Obama began as president making clear he wanted to devote more resources to Afghanistan, despatching 21,000 extra US troops to the country. In southern Helmand on Thursday, those troops began the fightback.

The Obama administration is right to have begun this full frontal assault on the Taliban’s strongholds. Of course, as Mr Obama recognises, many of Afghanistan’s problems can only be solved by action outside the military sphere. The security of the region depends on stability in Pakistan as much, if not more, than Afghanistan. Success in Afghanistan also depends on boosting civilian and humanitarian assistance from the west.