FORT IRWIN, Calif.—The 1st Infantry Division's 2nd Brigade is supposed to represent the Army's new model—small and nimble. Lt. Col. Jason Wolter, a battalion commander in the brigade, said, half joking, he would conduct overseas training missions this year with "just the uniform on my back."
Yet, the brigade landed here at the National Training Center ready for a full ground-war assault: 58 Abrams Tanks, each weighing 68 tons, along with 115 of the 33-ton Bradley Fighting Vehicles, a clutch of Humvees and a small fleet of drones.
The apparent contradiction illustrates the Army's dilemma. As it prepares for peacetime budget cuts, the Army must shrink. But Pentagon officials say reducing ground forces too much would leave the U.S. vulnerable to threats by such countries as North Korea or Iran. That means continuing to train with tanks, heavy weaponry and big formations—and, in the view of some military analysts, pulling the Army back to its roots and away from its promised future.
For years, there have been calls to shrink the Army, focusing on smaller, more-expeditionary operations. Now, U.S. military officials say it is finally time to decide the right balance of size, strength and security.
Military spending cuts of nearly $1 trillion are slated over the next nine years under current law. And with the winding down of operations in Afghanistan, the U.S. looks to end a decade of counterinsurgency fights that have achieved mixed results, at best, leaving Americans to question the value of long ground wars.
The Army is seen by some military analysts as a force from a past age, when wars were decided by tanks and artillery and the U.S. had the luxury of weeks or months to transport men and materiel to war zones.
Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey and Army Chief of Staff Gen. Ray Odierno, say they want to reorganize U.S. ground forces to focus on smaller units with greater lethal force, fewer casualties and faster deployment.
The days of "Industrial-age big formations with months to set the theater" are "if not gone, are going," Gen Dempsey said. "The kind of threats we can anticipate are rapidly developing threats."
These same military reformers, however, say the Army must be ready for a full range of operations—from training allies to humanitarian relief missions to counterinsurgency fights to old-fashioned tank battles.
Congress spent the last decade asking if the Army was big enough to simultaneously fight two ground wars. Lawmakers now must decide what to spend on such immediate missions as cyberdefense, training, no-fly zones, naval amphibious operations—and how much to set aside for any future ground war.
John Nagl, a retired Army Lt. Colonel who teaches at the Naval Academy, is among those who say the Army hasn't fully embraced new ways to fight and win wars without massive armored forces.
The Army's "organizational culture continues to focus nearly exclusively on state-on-state wars," he said, not the type of conflict he believes the U.S. is more likely to face in the future.
"They appear to be unwilling to make that next big step," Mr. Nagl said, toward reorganizing the Army for more work advising and training troops of allied nations, for example.
Pressure on the Pentagon is building. The 2011 Budget Control Act, which mandated across-the-board cuts known as the sequester, will cap military spending at $589 billion when the law expires in 2021, roughly the spending level of 2007.
Lawmakers in both parties criticize the automatic cuts but undoing them will be difficult. Military leaders and the Obama administration have pushed, unsuccessfully, for a so-called grand bargain, a combination of spending cuts and tax increases to both shrink defense cuts.
The current spending reductions aren't as deep as the cuts after Vietnam or the breakup of the Soviet Union, said military officers, but they will land faster. Next year, for example, the Army must cut its spending by as much as $14 billion.
The Army is the largest military branch and—with salary, pensions, health care and other costs rising much faster than inflation—the most expensive. A single soldier costs the Army an average of $531,427 a year when at war overseas and $118,368 when garrisoned.
Already, the Army has agreed to cut 80,000 people from its active-duty force, from a post-cold-war high of 570,000 in 2011. Retired Adm. Gary Roughead, the former chief of Naval operations, recently proposed bringing the Army down to 290,000, a suggestion that angered many Army officers.
Defense officials said the Army must shrink by an additional 100,000 soldiers if the across-the-board cuts remain, bringing the service to 390,000.
Other branches of the U.S. military are more secure, according to defense analysts. China's rise has cemented the Navy's importance. The Marines, used in military crises and humanitarian disasters, have a protected mission. The Air Force has fighter jets, as well as lethal, unmanned drones that can strike without immediate risk to U.S. troops.
"It is almost like the Army needs a therapist," said a senior Army official. "Go lie down in a dark room and think about what does the nation expect of me and how am I going to do that."
In World War II, the Army deployed divisions of 20,000 men who made up a mass convoy of mechanized infantry, artillery, medics, quartermasters, drivers and cooks. Few countries can fight the U.S. on those terms, even now.
During the Iraq war, the Army shifted focus from large divisions to the 3,500-person brigade. The idea was to make units more flexible. But even the brigade may be too big.
In the past decade of war, Gen. Dempsey said, most U.S. casualties have struck the Army's nine-soldier squads, its smallest unit. Giving squads better communications equipment and weapons would allow the Army to reduce casualties, lower the number of troops needed and speed deployments.
"I challenged the Army instead of looking at itself from the top down, look from bottom up," Gen. Dempsey said.
Gen. Odierno, Gen. Dempsey's successor as Army chief of staff, said his vision of a new Army looks to preventing wars as much as fighting them. He has assigned units around the world to train local military forces. The goal is to improve security in trouble spots without a U.S. military intervention. So-called regionally aligned forces can be deployed quickly in a crisis.
"Warfare is changing," Gen. Odierno said. But even so, the Army can't turn its back on traditional combat operations that require moving heavy armored forces over long distances, he said: "There are some conventional things we have to be prepared to do—North Korea, Iran. If we don't have the capability we lose our ability to deter."
Todd Harrison, a defense budget expert at the nonpartisan Center for Strategic and Budgetary Assessments, said the Army must assess the role of tank battles, given the global advantage of U.S. air power.
"The mind-set right now is we use the Army to invade or stop the invasion. But we may be at the point where [the Gulf War of] 1991 is the last tank-on-tank battle we are going to see," Mr. Harrison said.
Others, including Mr. Nagl, say the Army should step up its role of training and advising the military in other countries. The Army could, for example, create an advisory corps of experienced leaders and midgrade officers to serve as a military backbone for threatened allies, which provide the foot soldiers.]
A common theme of radical reform is specialization: Heavy forces moving to reserve status and the Army's lighter forces kept on active duty.
For now, Army units continue training to challenge well-armed nation-states on large battlefields, part of the practice by the 1st Infantry Division's 2nd Brigade at Fort Irwin's National Training Center.
A new war simulation tests the ability of commanders to fight different kinds of battles in a short amount of time: urban combat, counterinsurgency, partnerships with local forces and tank warfare. The idea, Gen. Odierno said, is to prepare leaders for all forms of enemy.
In the course of two days, Lt. Col. Wolter, one of unit's battalion commanders, sprinted across the battlefield to oversee his forces. They cleared a "city" of several hundred buildings, stopped a riot in the streets, met with factional leaders, cajoled a "partner nation" security force to join the fight and maneuvered tanks to cut off a sneak attack by an opposing armored force.
"It was some of the toughest training," said Lt. Col. Wolter, a West Point graduate and veteran of Iraq and Afghanistan. "It forced me to think harder."
In one scenario, a squad of soldiers entered one of the largest cities in the training area, known as Razish. A pretend resident of the city had just been executed by an opposing religious sect. But the squad continued on their assigned mission to scout the edge of the city without responding to the killing.
The officers overseeing the scenario said the soldiers, by not detaining any suspects in the attack, failed to show residents they cared about their safety.
Col. Paul Calvert, the lead coach, then hiked up the number of insurgents in Razish, from about a dozen to more than 40, making the fight that in his script would erupt later far more difficult to control.
The exercise, known as "Decisive Action Training," seeks both to preserve combat skills honed in Iraq and Afghanistan and revive the large-scale battle tactics last used in the 1991 Gulf War.
"We are transitioning the Army to be a little more agile," said Lt. Col. Jack Murphy, the director of operations at the training center. "We have essentially been doing counterinsurgency for the last 11 years. Who has experience doing force-on-force with tanks?"
Some senior Army officials said they would have preferred practice in training local forces—work the brigade is assigned to perform this year in Africa—rather than battling tanks. "It doesn't pass the common-sense test," said one.
Major Fernando Lujan, recently a fellow at the Center for a New American Security and now in Afghanistan with Army Special Forces, said such training swings back to the pre-9/11 military. "People are being told to go back to the National Training Center and pretend we are fighting World War III," he said.
Brig. Gen. Ted Martin, the commander of the National Training Center, said the training designers wove in many elements of war, past and present.
"From a squad of nine under the control of a staff sergeant all the way up to the brigade commander, what we are doing is trying to get these people out of their comfort zone," he said.
A brigade must be ready to go anywhere in the world for any kind of fight, he said. For a heavy unit like the 2nd Brigade, that means being ready to ship its tanks and other armored fighting vehicles to the Korean peninsula in the event of war.
And Army leaders are quick to remind people of the quip by former Defense Secretary Robert Gates about the Pentagon's always perfect record at predicting the next fight: the armed forces are always wrong.