I think that the future for check points on roads is that the soldiers stay safe in the blockhouse remotely controlling androids that look in the trunk of the car. Urban warfare will undergo a similar transformation. The soldiers stay in the armoured car operating the remote controls. The android kicks in the door, goes into the house and is blown to pieces by the booby trap.<p>In this scenario America is no longer constrained by human casualties but is instead constrained by the manufacturing capacity to make up loses of robot warriors.