After a decade of cuts that have shrunk the armed forces by 36 percent, the nation's military leaders say the reductions may have gone too far, and they are starting to push for a troop increase.

Pentagon officials warn that a three- or four-fold increase in peacekeeping and humanitarian relief operations since the end of the Cold War is straining the current level of 1.37 million active-duty service members.

"The demands being placed on the total force are starting to outstrip the supply of men and women in uniform and equipment to meet those increasing demands," Gen. James L. Jones, the new commandant of the Marine Corps, testified at his Senate confirmation hearing last month.

Coming at a time of rising budget surpluses and strong bipartisan support for higher defense spending, a Pentagon pitch to reverse the long decline in U.S. troop levels would seem a natural political play. But it is by no means certain that the Clinton administration will support such a move, having already promised billions of dollars from projected surpluses to modernize weapons and provide military pay raises.

Defense officials may also find themselves hard-pressed to explain why, in an era of advanced weaponry delivering more punch with fewer operators, the military needs more soldiers.

None of the service branches has yet submitted a formal request for additional troops, but military leaders from each one have indicated -- in public or private comments to government officials or journalists -- that such requests are under serious consideration.

The Army -- feeling most burdened as a result of "pop-up" crises that have turned into extended policing operations in places such as Haiti, Bosnia and Kosovo -- is talking about adding 20,000 to 50,000 soldiers, on top of the current authorized level of 480,000. The Marines have floated a possible increase of 5,000, which would bring their strength to 177,000.

The Air Force, now at 360,000, has said it could use at least 3,000 additional troops to help create 10 "air expeditionary forces" and permit a more orderly rotation of forces for overseas missions, with less disruption to family lives and training routines. And the Navy has signaled that it will resist planned reductions below its current 372,000 sailors and is thinking of seeking more ships and personnel.

Senior civilian Pentagon officials and many outside analysts remain skeptical about the need for a broad rise in forces. While acknowledging that shortfalls exist in a few specialty areas -- such as electronic jamming and aerial surveillance aircraft and crews -- they contend that the strain on the rest of the military has more to do with poor management than with insufficient numbers.

In the Army's case, in particular, defense experts assert that more extensive use of reservists and private contractors could ease the load on active-duty troops. Deeper reductions in nonoperational units also could permit increases in the forces most often deployed, without requiring a rise in overall troop strength, some experts argue.

The services already are having trouble recruiting to current levels, let alone trying to fill expanded ranks. The Army expects to fall 6,800 short of this year's goal of 74,500 recruits. And last week, the Air Force predicted it would end this fiscal year 2,500 recruits shy of its target of 33,800 -- the first such shortfall since 1979.

Pentagon complaints last year that excessive wear and tear on the armed forces were damaging readiness led the Clinton administration early this year to add $112 billion to defense spending plans through 2005 -- the first multiyear rise in military spending in 15 years. In light of that boost -- much of which was earmarked for new weapons, spare parts, training and higher pay and benefits -- senior administration officials appear reluctant to provide still more funds for additional troops.

"I think they're staking out some positions," one senior civilian official in the Pentagon said of the services' murmurings about desired troop increases. "A lot of what we're seeing is just posturing."

But the Republican-led Congress, which has been trying to one-up the administration in bolstering military readiness, may be receptive to appeals for enlarging the force, especially with the 2000 elections in view and federal budget surplus projections on the rise. The chairman of the Senate Appropriations Committee, Ted Stevens (R-Alaska), already has expressed sympathy for bolstering the Army's ranks.

Other lawmakers agree that the military is strained, but blame the administration for overcommitting U.S. forces. They would like to see a withdrawal of the 6,200 American troops still deployed in Bosnia, the 340 soldiers serving in Haiti and the 900 GIs monitoring peace between Israel and Egypt on the Sinai Peninsula.

Such views would seem to ensure, at a bare minimum, a vigorous political debate about just what the armed forces should be doing and how large a military the United States needs.

From the armed services' perspective, the primary problem is that too many troops are deployed too frequently, spending too much time away from their bases and families.

"The crux of the issue is the family separations and the expectations of the families," said David Chu, a Rand Corp. vice president who is conducting a study for the Army on its troop flow. "In a peacetime environment, when a nation's back is not up against a wall, there is a limit to family patience with these separations."

But among the puzzling aspects of the military's cry about being overworked is that, even with the steep increase in overseas missions, only a small percentage of U.S. forces are in the field at any given time. The Army, for instance, has on average about 30,000 soldiers deployed daily in more than 70 countries -- out of a total force of 480,000.

Why, then, does it feel so stressed?

Army officials explain that only about 60 percent of its personnel are earmarked for actual operations. The rest work in institutional jobs -- as recruiters, trainers, acquisition clerks and Pentagon planners, for example -- or are in transit between assignments. Before the Army asks for more troops, some defense experts say, it needs to find ways of shortening its long support tail and growing its combat teeth.

Both the Army and Air Force are taking steps to streamline their bureaucracies and better employ the forces they already have. The Army plans to trim its heavy armored divisions by 15 percent, to 15,700 troops from the current 18,000, and to experiment with lighter strike forces. The Air Force plans to launch its reorganized air expeditionary forces this autumn.

Even so, the U.S. military remains structured largely for war, not for rotating troops in and out of smaller-scale peacekeeping assignments.

"Given the size of the building blocks around which the Army and Air Force are still organized, they're right to say they may be pushing the force too hard," said Michael O'Hanlon, a defense expert at the Brookings Institution. "But I question whether you need to still build divisions in 16,000-man increments and air wings in 72-plane increments. They need to make the individual pieces or building blocks smaller, and if they do that, they can get by with the same number of people."

Besides, the price of more troops would be high. Adding 20,000 soldiers, for instance, would cost the Army an extra $1 billion a year in pay and benefits and another $1 billion in operational, training, housing and other costs. The $2 billion total would amount to about one-quarter of what the Army plans to spend on new weapons purchases.

Dwindling Ranks

The number of active-duty military personnel has decreased 36 percent since 1989.

IN THOUSANDS

Marines: 172,000

Air Force: 360,000

Navy: 372,000

Army: 480,000

SOURCE:Department of Defense

CAPTION: Gen. James L. Jones, commandant of the Marine Corps, at Senate hearing.