As the Obama administration winds down more than a decade of war, the budget request — only fragments of which were released Thursday — is supposed to account for cuts of $487 billion in projected spending over the next 10 years.
Pentagon officials said their proposal represented tough choices, but the biggest cuts appeared to be in the Defense Department's plan to reduce the number of U.S. ground forces to slightly more than on Sept. 10, 2001, before the wars began.
At the same time, the department proposed increasing spending on technology and major weapons systems, after a strategic announcement earlier this month in which defense officials said they must be ready for all kinds of warfare and proposed greater use of unmanned aircraft and a more agile ground force.
It wants to raise spending on drones by 30 percent, delay spending on the costly and controversial F-35 Joint Strike Fighter and fund a new bomber and a sea-based vessel that would allow drones and helicopters to take off from international waters. It wants to maintain current spending levels on missile defense and nuclear weapons while increasing spending on cybersecurity.
Tthe department sought to assert that it was simultaneously taking risks and not losing any conventional capability. It said it was responding to growing fiscal pressures because this proposal represented the biggest cut it had made in a decade.
Their proposal, officials have said, carries risks because the U.S. military no longer would be able to fight two wars simultaneously and might be required to make difficult decisions about military priorities.
"The primary risk lies not in what we can do but in how much we can do and how fast we can do it," said Army Gen. Martin Dempsey, the chairman of the Joint Chiefs of Staff.
For the 2013 fiscal year, the department requests a $525 billion base budget — a $6 billion decrease from the current budget — and an additional $88.4 billion in supplemental funding for the war in Afghanistan, down from $115 billion this year.
For 2014, the request for the base budget — which excludes war spending — jumps to $534 billion; by fiscal year 2017 it reaches $567 billion.
The department, which expanded the size of its ground forces quickly over the past decade to support the wars in Iraq and Afghanistan, plans to cut the Army by 2017 to 490,000 soldiers from the current 562,000. Over the same period, the Marines would shrink by 20,000 to 182,000.
That would still leave a larger military than before the wars started. In 2001, there were 480,000 soldiers and 180,000 Marines.
In line with the smaller forces, the Pentagon calls for retiring planes that transport troops, including 27 C-5As and 65 C-130s. The budget also proposes modest limits on pay raises that would take effect in 2015 — after the U.S. combat mission in Afghanistan is expected to be over — and increases in health care premiums.
Panetta said the administration would ask Congress to authorize another round of cuts at U.S. military bases through the base realignment and closure process, which was last employed in 2005. He didn't offer specifics.
Regardless, the suggestion alone could spark outrage on Capitol Hill, especially in an election year. Sen. Carl Levin, D-Mich., the chairman of the Armed Services Committee, said Thursday that he wouldn't support closing domestic bases before U.S. bases in Europe were shuttered.
Rep. William "Mac" Thornberry, R-Texas, called the proposal for a new BRAC round "ridiculous, and there is likely little support in Congress for such a thing, on either side of the aisle or either side of the Capitol. It will cause disruptions across the services, yet offer little in terms of savings."
Announcing the results of a strategic review last month, the Defense Department said it would increase its focus on Asia. Its budget proposal reflects that, with spending for an 11th aircraft carrier and weapons system that could respond to China's growing military strength.
The department said it planned to cut two brigades from Europe and, according to Panetta, commit more troops to Asia, but he didn't offer specifics Thursday.
The department plans to save billions more by delaying production of the F-35, the most expensive weapons program in U.S. history. Bloomberg News reported that the projected expenditure on the system would be $9.2 billion, which would buy 29 of the fighters, 13 fewer than initially planned.
Officials said they hoped that the delay would give developers time to correct the myriad technical problems plaguing the program. But experts warn that prolonging production could raise its costs.
The Obama administration is expected to announce its full 2013 budget proposal in early February.