The hefty sum, which is roughly $4 billion lower than the Pentagon's own estimate, covers the full gamut of costs associated with a permanent expansion of the military's principal ground forces, including personnel, healthcare, operations, procurement and construction accounts.
Senate Armed Services Chairman Carl Levin, D-Mich., who has questioned Pentagon officials on the administration's plans, sought the CBO cost estimate, making it a potential issue for the committee when members mark up the fiscal 2008 defense authorization bill next month.
Though supportive of congressional efforts to grow the Army and Marine Corps, which have borne the brunt of the extended combat operations in Iraq and Afghanistan, Levin has questioned Pentagon officials on whether the administration's plan may be too late and too costly to be worthwhile.
"The administration's proposal to increase the permanent end strength and structure of the Army is welcomed, although late," Levin told Army leaders at a hearing last month. "Had we started in earnest to grow the Army even four years ago, our forces today would be less stressed and more ready. We must guard against merely creating a larger version of a less ready force."
The White House, taking cues from then-Defense Secretary Donald Rumsfeld, consistently opposed bipartisan congressional efforts to increase the size of the Army and Marine Corps over the last several years. It argued repeatedly that the president already had enough authority to adjust the size of the services to respond to emergencies and dismissed any required increases in so-called military end-strength as unaffordable.
But with operations in Iraq and Afghanistan continuing to place heavy demands on military personnel with no immediate signs of abating, President Bush announced in January he wanted to add 65,000 soldiers and 27,000 Marines to the active-duty services over the next five years.
This increase would be permanent, compared to Bush's plans for an immediate, but temporary "surge" of additional ground forces to Baghdad and Iraq's Anbar province. In addition, the military has proposed a permanent expansion of the Army Reserve and Army National Guard by another 9,200 soldiers.
For the active-duty Army, the substantial growth in its force will cost $76.3 billion by 2013, according to CBO, which released its estimates late Monday. The Marine Corps, meanwhile, will need $31.7 billion to cover the expansion in its force.
By 2014, the Defense Department will need another $14 billion annually to pay for the larger force, CBO estimated.
Gordon Adams, former OMB associate director of national security, said Tuesday that the growth of the ground forces is not needed and ultimately will "bleed the Pentagon dry."
"It will do nothing to alleviate force stress in Iraq, unless you assume we are there in large numbers for another three [to] five years," said Adams, now a fellow at the Woodrow Wilson International Center. "It is an expansion without a mission, thereby putting the expansion cart ahead of the strategic horse."
But Army boosters argue that ground forces will be deployed heavily for decades to fight the war against terrorism. Without a larger pool of soldiers and Marines to draw from for deployments, the forces will be stretched too thin.
The Army right now "does not have the resiliency or the strategic depth" it needs to meet constant deployment demands, said retired Lt. Gen. Ted Stroup, a vice president at the Association of the U.S. Army. "You need more brigades and you need more soldiers to man those brigades."