One welcome dividend of Donald Rumsfeld’s departure from the Pentagon is that the US will now have a chance to rebuild the Army he spent most of his tenure running down.

Rumsfeld didn’t like the lessons the Army drew from Vietnam — that politicians should not send American troops to fight a war of choice unless they went in with overwhelming force. One of the first challenges for the next defence secretary and the next Congress is to repair, rebuild and reshape the nation’s ground forces. Keeping the Army in its present straitjacket would bring bigger and more immediate problems. Even assuming an early exit from Iraq, the Army’s stren-gth needs to be increased by 75,000 to 100,000 troops.

If the new Pentagon leaders and the new Congress are prepared to take on the military contracting lobbies, they could take as much as $60 billion now going to Air Force fighters, Navy destroyers and Army systems designed for the conventional battlefield and shift it to training and equipping more soldiers for unconventional warfare. Congress also needs to hold the executive branch accountable for the use of American troops abroad. Rebuilding the Army and Marine Corps is an overdue necessity.

But it is only the first step toward repairing the damage done to America’s military capacities over the past six years.