Last year, when Congress ignored his counsel and mandated a permanent 20,000-soldier increase for the Army, the tug of war played out as a battle of wills, pitting the Pentagon's vision of the future against Congress's concerns about the present. Now, the House is poised to take up the cause again, considering a measure that would tack on another 10,000 troops.

As the war in Iraq enters a crucial period - one that could help decide when troops can start coming home - it is an issue that cuts to the core of the military's prospects for success. On Wednesday, legislators must weigh whether more soldiers will help the military despite itself or simply add new budget, training, and recruiting burdens to an organization already pushed to its limits.

As was the case last year, the provision would merely be added to the National Defense Authorization Act - the Pentagon's 2006 budget. The subcommittee debate Wednesday could move the measure forward for a full House vote. But concern around the issue is such that several lawmakers - including Rep. Ellen Tauscher (D) of California and Sens. Jack Reed (D) of Rhode Island and Chuck Hagel (R) of Nebraska - have introduced bills to ratchet up the size of the Army and Marines.

Indeed, to some observers, even 10,000 more soldiers and 1,000 more marines are not nearly enough. "Although it's a good start, it's not going to solve the problem," says Thomas Donnelly, a military analyst at the American Enterprise Institute in Washington. "The correct amount would be 10 times that."

After the cold war, the size of the US Army shrank from 780,000 troops to about 480,000. In the context of a world where America's greatest enemy had collapsed, the reduction was logical and even necessary.

The war on terror, however, has changed the calculus, many analysts say. Afghanistan and Iraq have shown that the next phase of American military action will be manpower intensive, relying far more on boots and rifles than jet fighters and naval destroyers. In this context, 480,000 Army soldiers are insufficient to deal with "win the peace" in Iraq and to still be prepared for other threats from the Horn of Africa to the Taiwan Strait.

The evidence from Iraq, some say, bespeaks an Army on the brink: overdependence on citizen soldiers and a reliance on troops to take on two or three deployments. One of the resulting concerns is that they will be worn out and eventually leave - before or after the conflict is settled - hobbling the Army for years to come.

This war "has been way too demanding on ground forces," says Michael O'Hanlon of the Brookings Institution in Washington.

Pentagon officials note that they have acted on the issue, using emergency war powers to increase troop levels temporarily by 30,000. But so far, they have taken a dim view of congressional efforts to raise those figures even higher and make them permanent. Perhaps some part of the reluctance is just stubbornness, say critics, with the secretary unwilling to admit that his vision for a smaller Army was - at least in the case of postwar Iraq - potentially a mistake.

For his part, though, Rumsfeld has contended that it is a question of simple math: The United States still has 2.6 million active, Guard, and Reserve soldiers at its disposal, which should be adequate to maintain 150,000 troops in Iraq.

"That suggests that the real problem is not the size of the force per se, but rather the way the force has been organized over the years and the mix of capabilities at our disposal," Rumsfeld told Congress during this same point in the process last year. "And it suggests that our challenge is considerably more complex than simply adding more troops."

This challenge is a part of the secretary's broader goal: transforming the military from a force arrayed against the relatively static threats of the Soviet Union to one capable of coping with unpredictable flash points. It means recasting the military into smaller chunks - brigades rather than divisions - that can be moved around more freely. It means redistributing duties throughout the military so that active-duty soldiers are not sitting behind a desk or trained in a skill more suitable to mechanized cold-war warfare. And it means pulling back soldiers from installations in Europe so they are ready to be redeployed in new global hot spots.

All this takes time. And Congress's push to add more troops before the process is finished only adds more duties to the complex job already under way. "Ask the question [of Army size] in another two years," says Daniel Goure, a military analyst at the Lexington Institute in Arlington, Va. "Don't add additional problems in the guise of doing good."

After all, with the ongoing recruiting problems, it's not at all certain that the Army could meet higher goals. And more troops mean a much bigger bill, not just for salaries, but also for training, supplies, housing, and healthcare. If the cost of the war escalates, the Pentagon could be forced to cut other areas, such as research and weapons. To some, these are just pet projects that could use a little fiscal restraint. But to others, they are the source of American military dominance.

Says Mr. Goure: "If you confront the military with a choice: Would you rather have a larger, poorly equipped Army or a smaller and well-equipped Army? They would go for the latter every time."

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