Gen Dempsey provides his broad vision for 2020

The US military's top officer has broadly outlined his vision for a future force that may mostly deploy for distributed operations, but can be aggregated when necessary.

Training and equipping for the US military in the past primarily emphasised massing forces, but, for operations in Iraq and Afghanistan, the military had to learn how to disaggregate when necessary.

"My instinct tells me that the 21st century will be a period where we will be asked to apply our military instrument decentralised, distributed, [and] disaggregated, but never lose the ability to aggregate it when necessary," said US Army General Martin Dempsey, chairman of the Joint Chiefs of Staff.

"That's going to be a really hard change for us to make, but I think it's one we really have to think about making," Gen Dempsey said at the Air Force Association's annual conference in National Harbor, Maryland, on 19 September.

He added that he believes the future US military will have to be able to operate in a world characterised by two seemingly antithetical realities: a globalised planet with economic interdependence and myriad connections through information technology, and a world in which geography may play a more important role than technological advancements.