Sitting around the Cabinet Room table, Bush and Dick Cheney promised to make good on their campaign pledge to modernize the military with a new generation of advanced weapons–and said Defense Secretary Donald Rumsfeld would lead the way if Congress would only quit its carping. “You have to give Rumsfeld more freedom,” Cheney told them. “Dick’s right,” Bush cut in. “Let him do his job.” According to a White House official who was in the room, Bush told the lawmakers that Rumsfeld had his blessing to kill off aging or unneeded weapons programs to free up dollars for innovation. At the top of Rumsfeld’s hit list: the Crusader, an $11 billion big-gun program still in its infancy–and a favorite of several Capitol heavyweights. The meeting was over. But the showdown was just beginning.

As promised, last week Rumsfeld unceremoniously declared the Crusader dead. “Our country needs an Army that is mobile, lethal and deployable,” he said on Wednesday. Crusader critics complained the rolling, 40-ton artillery gun was a slow and heavy cold-war relic in an age of smaller-scale, mobile combat. Predictably, members of Congress–including many Republicans–were miffed, and are fighting the decision. “The Defense Department is afflicted with hubris,” says one Senate Republican. “They are intoxicated by their success in the war on Afghanistan and don’t feel like they need to have much to do with Congress.”

It’s not the first time Rumsfeld has heard a comment like that. His prickly, impatient manner has made him plenty of enemies in Washington. Before September 11, Rumsfeld’s combative stewardship of the Pentagon provoked so much criticism that officials speculated he would be the first cabinet secretary to quit. But after the terrorist attacks, that same imperious style made Rumsfeld an unlikely wartime celebrity among the public, which saw him as tough and plain-spoken. Now Rumsfeld intends to use his new clout to push the Pentagon and Congress to overhaul the armed forces.

Of course, every Defense secretary in memory has made a similar pledge, with less than impressive results. Rumsfeld has an advantage: the backing of a popular wartime president. But he will face much tougher opposition when, as he plans, he goes after more entrenched weapons systems, especially sacred combat aircraft. As one top Senate aide put it, “The Crusader is the low-hanging fruit.”

The Crusader fight is at least in part about a cautious Army clinging to what it knows best: heavy tanks and big guns. (In a bit of Beltway intrigue, the Army was caught lobbying for the program on Capitol Hill–at least until Rumsfeld got wind of it, and a mid-level aide to Army Secretary Tom White obligingly resigned.) And it is certainly about the time-honored practice of congressmen fighting to protect lucrative military contracts in their home states. The Crusader’s strongest backers, Rep. J. C. Watts and Senators Jim Inhofe and Don Nickles, all Republicans, are from Oklahoma, where the gun would have been built.

But the Army wanted Crusader for another reason: Rumsfeld’s still-evolving ideas about the likely shape of future wars have left it uncertain about its mission. Last year Rumsfeld downgraded the “two major-theater wars” scenario that has structured the military since the end of the cold war, and asked the Pentagon to focus on new threats as well. But the military is still waiting for the civilians at Defense to spell out just what that means. Should war planners put their dollars into large-scale combat or small? And do they have five years or 20 to prepare? Unsure of the answer, the brass opted to develop a wide range of weapons.

First conceived in 1994–in response to the gulf war, not the cold war–the Crusader would clip along at up to 40 miles per hour, pausing to fire rocket-propelled shells at targets more than 25 miles away. In short, it would be useful in large-scale battlefield fighting, a kind of war that currently seems unfashionable but may be necessary in the future (think Iraq).

Rumsfeld is convinced that the war in Afghanistan shows the new way the military must fight. Not with a traditional Desert Storm buildup, but using precision strike weapons–guided by only a handful of U.S. forces on the ground. In that scenario, the Crusader would be utterly out of place. Rumsfeld wants to spend the Crusader’s dollars to fund what he sees as weapons of the future, like Global Hawk and Predator, the high-flying drones used effectively in Afghanistan. To replace Crusader, his team is looking at Excalibur, a satellite-guided shell with great accuracy. Looking further out, the Army is doing concept studies on a new family of light, fast combat vehicles.

Rumsfeld’s also girding for mightier bureaucratic battles to come. Last week his acquisitions chief warned that other popular new systems, including the Marine Corps’s tilt-rotor V-22 Osprey, could be canceled unless its technical glitches are fixed. And Rumsfeld has ordered the Air Force to look at cutting by half its order of the short-range F-22. The Crusader’s backers on Capitol Hill, meanwhile, aren’t quite ready to give up. Late last week the House passed a bill that would keep the gun alive at least until next year, giving the Army time to complete an analysis of possible alternatives. The Senate might pass a similar delay, says one Armed Services staffer. Not because anyone thinks it’ll help save the weapon–but “to teach Rumsfeld to mind his manners.”