What will the U.S. Army be like in the year 2043? It might seem like a long way off to some, but Pentagon planners are hard at work figuring out what shape its ground forces need to take to stay preeminent in the coming decades. There are two main challenges that have to be addressed: the first is the pressure of shrinking budgets for the foreseeable future and the second is China's increasing defense expenditures to create a military capable of projecting power into the South China Sea.
Asking the Army to do less with more is a bit cliched, but it is unfortunately true. It appears that one of the ways the Pentagon will deal with this is to shrink the forces while moving ahead with replacing and updating equipment and systems. This can work up to the point where the Army finds itself without enough infantry and armor brigades to carry out relatively large-scale and sustained operations against for example, Iran and terrorist groups in the Horn of Africa. No one really knows what the exact numbers are, but recent experience with OEF and OIF suggest the point has already been reached.
The Pentagon will have to come to terms with the economics of men versus machines - how many combat brigades it can trade for new helicopters and tanks.