WASHINGTON - On the third floor of the Pentagon, behind closed doors, Defense Secretary Donald H. Rumsfeld and a coterie of advisers are quietly fashioning what may be a drastically altered military for the 21st century.
Security is tight. The officers and civilian defense analysts providing information to Rumsfeld and his team are sworn to secrecy.
Not much has leaked out, but some analysts - reading tea leaves based on the officials involved and the marching orders issued by President Bush - say Rumsfeld's goal might be a major transformation of the roles, missions and weapons of the armed forces.
"Potentially, one of the biggest shifts in the century, more dramatic change than in earlier reviews," said Steven Kosiak, director of budget studies with the Center for Strategic and Budgetary Assessments, a Washington research center.
Rumsfeld's blueprint, expected to be unveiled in the spring, will detail his view of the threats the United States faces, the size of the military, the way forces should be deployed, which weapons should be built and which are expendable.
The Rumsfeld review will be the "underpinning" for Pentagon spending, according to Bush's $310 billion budget plan, which faulted the military for organizing and equipping itself to fight the long-departed Soviet Union, not future adversaries.
But without a greater role in its formation, the Pentagon chiefs might be reluctant to go along with the Rumsfeld game plan and unwilling to assist wholeheartedly in selling it to Congress, which controls the purse strings.
A military that relies on aircraft carriers, attack aircraft and tanks must look to more futuristic technology, said the budget plan Bush sent to Capitol Hill late last month.
Elaborating on that presidential dictum, officials say victory no longer can be assured by brute force, but instead requires information, stealth and speed. They say pilotless drones that can bomb or spy, small, missile-packed ships, satellites and miniature sensors that detect the enemy will dominate the battle space of the future.
Some contractors and military officers fear that cherished weapons systems may fall victim to the review, especially because the budget plan says the military must move beyond "incremental" change.
Some say the sweep of the Rumsfeld review could be unprecedented, dwarfing earlier efforts to reshape the military.
One review, in the late 1940s, designed and organized a military to fight and contain the Soviet Union. Another, in the early 1950s, placed emphasis on building a U.S. nuclear missile and bomber force.
The last major strategy effort was more than a decade ago, the "base force" plan devised by Gen. Colin L. Powell, then chairman of the Joint Chiefs of Staff and now secretary of state.
That plan slashed the number of armed forces personnel from 2.1 million to 1.6 million; reduced the number of aircraft carriers from 14 to 12; chopped weapons programs, including the long-range B-2 stealth bomber; and crafted a strategic doctrine that required the military to equip itself to fight two major wars nearly simultaneously.
"I think it was a giant step toward building a post-Cold War force," said Deputy Defense Secretary Paul D. Wolfowitz, who as a top Pentagon official in the administration of President George H. W. Bush helped Powell push the base force plan through Congress. "But it was largely a downsizing of the force. We didn't have a lot of time to think about the new shape of the force. We hadn't thought a lot about the new threats."
Wolfowitz is a key figure in the new review, which is expected to increase the focus on terrorism and the proliferation of ballistic missiles and chemical and biological weapons. It also is likely to question whether the two-war strategy still makes sense, said defense analysts and congressional aides, who have seen some of the proposals.
Rumsfeld picked up on those themes last week during a news conference and again raised questions about the weapons in the U.S. arsenal.
"Our interest is in recognizing that ballistic missiles constitute a threat and weapons of mass destruction constitute a threat," he said. "[These] threats constitute more of a threat today than the risk of a major land, sea or air war, where some country decides to threaten Western armies and navies and air forces."
One element of the military of the future that Bush envisions is well known: He wants to deploy a missile defense system to protect the United States and its allies.
Much less is known about what else Rumsfeld and his team are considering, but officials familiar with the preliminary work said a number of options are under consideration, among them:
The Navy might be reduced from 12 carriers to 10, while getting the green light for a new advanced destroyer, the DD-21, that could strike with its missiles at enemy targets farther inland.