At 79, Marshall is in some ways Washington’s last Wise Man–the last senior official who was “present at the creation,” in Dean Acheson’s phrase, of the nuclear age. Brilliant and inexhaustibly curious, monkishly devoted to his work (he and his wife live in a small rented apartment in Foggy Bottom; his one indulgence is vintage wine), Marshall has a long record of prognosticating broad trends, like the decline of the Soviet Union. He has also nurtured a coterie of loyal–and powerful–proteges. They refer to themselves as his “sons” and to Marshall’s department, the obscurely named Office of Net Assessment, as “St. Andrew’s Prep.” Alumni include the current secretary of the Air Force and the chief of staff of the deputy secretary of Defense.

Among Marshall’s many fans is Secretary of Defense Donald Rumsfeld, who has asked him to help the Bush administration define America’s defense needs for the next several decades. In the perpetual race between America and its potential foes for deadlier weapons and smarter strategy, Marshall’s mission for a generation has been to answer, in effect, who’s winning? And, more importantly, how to get and stay ahead.

Now, in his deceptively quiet and non-confrontational manner, Marshall is pushing what he has termed a “revolution in military affairs.” Technology, Marshall argues, is transforming warfare and enabling weaker countries to challenge American military dominance. While Marshall has been careful not to spell out which parts of America’s arsenal should be junked, he has foreseen that the weapons of the future–precision-guided missiles–will turn some of the military’s most prized armaments, like the aircraft carrier, into fat targets.

It’s hardly news that some of the fabled weapons of World War II, like the tank and the carrier, are vulnerable 60 years later. “Smart” and “brilliant” weapons, long-range munitions guided by satellite and seeking their own targets, have been threatening to overwhelm heavy-metal forces and fleets for at least two decades. But the top brass has been loath to give up favorite toys, and congressmen fight to protect pet contractors in their districts. As one of the great bureaucratic survivors, Marshall, a civilian who never served in the military, has avoided taking on the generals and admirals who earned their stars by commanding carrier task forces and tank divisions. Rather, he has worked to create an intellectual framework aimed at making military strategists, as well as policymakers and politicians, smarter about future threats and how to meet them.

His first step is to try to shift the focus from Europe, the potential battlefield of the old U.S.-U.S.S.R. superpower rivalry, to East Asia, where, Marshall believes, China is seeking hegemony. In war games staged by Marshall–typically set decades into the future–Chinese satellite-guided missiles invariably devastate American carriers. Marshall uses historical analogies to make his point. He sees the current period as the rough equivalent of the 1920s. If America does not adapt to the new technologies, it may wind up like France, manning a Maginot Line easily outflanked by a blitzkrieg.

Marshall’s track record gives him credibility. A former expert on nuclear-war-fighting at Rand Corp., the Pentagon think tank, Marshall was one of the first to see the weaknesses of the Soviet empire. By studying obscure demographic and economic data, he deduced that the Soviets were in crisis–and spending a far bigger slice of its national income on defense than anyone had suspected. Marshall’s answer: spend the Soviets into the ground. When the Soviet empire collapsed after the Reagan-era defense-spending spree, Marshall seemed clairvoyant.

Bureaucratically, he has slipped up only once. In 1987 he persuaded Defense Secretary Caspar Weinberger to set up a Competitive Strategies Office. It indiscreetly suggested that carriers might one day be vulnerable to long-range missiles. The Joint Chiefs of Staff had the office shut down. Marshall is unlikely to make that mistake again: a mention of carrier vulnerability was recently deleted from an early draft of his strategy review. It will be up to Rumsfeld–and ultimately George W. Bush–to demand hard choices. In a 1999 campaign speech largely written by a Marshall disciple, Deputy Secretary of State Richard Armitage, Bush pledged to “skip a generation” of weapons. The president is expected to roll out that policy in late May, introducing Marshall’s review in a commencement speech at Annapolis. If Bush can accomplish this goal, it will be a testament to the wisdom–and staying power–of Andy Marshall.