Washington ? In the long months of planning Operation Iraqi Freedom, Gen. Tommy Franks had a ready answer when challenged on his unorthodox concept of starting his attack with light, fast-moving forces and augmenting them while the battle grew. “Speed kills — the enemy,” Franks said several times at the secret planning sessions, a colleague recalls.

But for all his foresight, Franks did not anticipate beginning the war in Iraq exactly as he did, or becoming the target of controversy and criticism over his battle plans. Franks’ surprise is understandable on the first point. But he should have been better prepared for the doctrinal challenges he now faces on the home front.

The Army four-star, who is the theater commander for the Iraq war, never dared to hope that the CIA would come to him on March 19 with this huge golden nugget: Two Iraqi officers the agency had recruited from Saddam Hussein’s inner circle had pinpointed a leadership compound where the dictator was expected to turn up that night. But that is exactly what happened, according to a reliable and detailed account of the opening hours of the war.

The intelligence windfall presented Franks with the kind of dilemma that has surfaced repeatedly in two weeks of a war being fought with speed and skill rather than banking on the Army’s traditional ponderous force.

Coalition aircraft had not yet taken out Baghdad’s air defense systems, the standard initial step in an air war that would have warned Saddam he was under attack. And cruise missiles would not reach the underground bunker where the leadership meeting would take place, the agency correctly informed Franks.

Within a few hours, the decision was made to seize the chance and take the risk — to begin the war by dispatching two F-117 Stealth fighters to drop 2,000-pound precision guided bombs on the underground bunker while cruise missiles destroyed the target’s surface structures. Both missions were accomplished without U.S. loss, and Saddam was reported by the agency’s Iraqi sources to have been carried off on a stretcher, blue in the face and taking oxygen. The two officers have since managed to escape from Iraq and are safe.

The night strike changed the procedures and initial campaign timelines that President Bush had approved in signing the war’s “execute order” on Monday, March 17. If Saddam had not left Iraq by March 19, the war was to have begun that night with attack helicopters and special forces units taking out isolated targets near the frontiers.

That was to have been D-Day. In a deliberate and dramatic reversal of the 1991 pattern of Operation Desert Storm, Franks set G-Day, the launch of ground operations, to begin 48 hours later. “But the night strike on Saddam’s bunker caused Franks to reverse his sequencing and move up the ground operations by 24 hours,” says one official involved in the planning.

Franks’ decision to hurl the Army’s 3rd Infantry and his Marine units deep into Iraq in the war’s opening days was a daring reversal of War Plan 1003, a document that had been on the shelf until Defense Secretary Don Rumsfeld told Franks to get ready for campaigns in Afghanistan and Iraq after 9-11.

The old plan reflected the Army’s traditional preference of reducing risk by increasing mass. It was drawn straight from Desert Storm and called for slowly building up heavy armor forces in Kuwait to turn back invading Iraqi forces. Rumsfeld, Deputy Secretary Paul Wolfowitz and Franks worked through new ideas that centered on risk being reduced more effectively by speed in the changed circumstances.

They were determined to avoid giving Saddam time to launch missiles with chemical warheads against Israel and its Arab neighbors, torch Iraq’s oil fields or launch new massacres that would send waves of Iraqi refugees fleeing into Turkey and elsewhere. They have been largely successful in these objectives so far.

But some of Franks’ own commanders have joined a chorus of critics who suggest that American forces are dangerously overextended and have outrun their supplies. He has been stung by this criticism, friends report, but is determined to prove that his “rolling start” concept is the best way to fight a war of liberation that puts a premium on avoiding Iraqi casualties and brings a quick end to combat.

Franks cultivates the image of being a plainspoken country boy. But he has impressed his superiors with a camouflaged mental quickness and flexibility. He is going to need exactly those qualities to overcome first the Iraqis and then those on his own side who argue that only large armies possessing overwhelming ground force can win wars.