'The IED problem is getting out of control. We've got to stop the bleeding.'

By 2002, some of these devices were considered obsolete and had been consigned to a warehouse shelf. But Navy specialists in Indian Head, Md., 30 miles south of Washington, reconfigured a jammer they called Acorn, which neatly matched the frequencies used by the Spider Mod 1 in Afghanistan. In November 2002, 45 days after the first plea for help from Afghanistan, several dozen Acorns began arriving at Bagram Air Base.

Army EOD experts distributed each device, mounting the gray box and antenna on Humvees and Special Forces sport-utility vehicles. Instructing soldiers in the nuances of wave propagation and other electronic mysteries proved challenging; one device reportedly was installed on a water truck that never left the base. Successful jamming meant troops had no way of recognizing that they were even under attack by a radio-controlled IED. Acorns could also interfere with radios and other electronics.

Still, Vines's "30 percent solution" was more than fulfilled. As one retired Navy captain later recalled of Acorn: "We expected it to last six months before the bad guys figured it out." Instead, more than 2,000 Acorns eventually outfitted the force in Afghanistan where, like the Spider, it would remain a fixture on the battlefield for the next five years.

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While U.S. forces parried the fledgling IED threat in Afghanistan, secret planning for the invasion of Iraq had accelerated. Little thought was given to roadside bombs as a serious obstacle to the American juggernaut. But U.S. strategists feared that Saddam Hussein would destroy his own oil production facilities rather than let them be captured. Scorched-earth tactics by retreating Iraqi troops in 1991 had turned Kuwait's oil fields into an inferno.

U.S. intelligence in early 2003 reported that wellheads in southern Iraq had been wired for detonation, and that Iraqi forces probably had the ability to use radio-controlled triggers to detonate those demolition charges. Jammers would be needed to secure the fields.

Even as the Navy converted Acorn into a battlefield countermeasure, Army engineers at Fort Monmouth, N.J., were working on their own mobile jammers. First in a laboratory and then in field tests, they modified an old system called Shortstop, originally built in 1990 as a footlocker-size gadget to confound the proximity fuses in incoming artillery and mortar shells.

By intercepting and modifying the radio signals emitted by such fuses, Shortstop tricked the shells into believing they were approaching the ground, causing them to detonate prematurely. Shortstop had been completed too late for use in the 1991 Persian Gulf War, and it was deployed to Bosnia only briefly. A Pentagon inventory showed that the Army had almost 300 systems in storage.

With different computer chips and a cleverly modified ham radio antenna, Shortstop made an admirable jammer. The wife of one Fort Monmouth engineer collected miniature kitchen witches that inspired a new name for the device: Warlock Green. After final fixes in California, five Warlocks were shipped to Kuwait in time to accompany the invasion forces plunging into Iraq in March 2003, according to a senior officer involved in the effort.

The countermeasure proved unnecessary. Not a single oil well was rigged for radio-controlled detonation. Some oil facilities were sabotaged, but the damage was less grievous than feared.

Yet the Army jammer had found a home on the battlefield. As Shortstops were transformed into Warlock Greens -- each device cost about $100,000, according to a contractor involved in the program -- they were shipped in large Rubbermaid storage cases to Afghanistan, where a technician laminated his business card onto the devices so soldiers knew whom to call for help. Others would be packed up, driven to the Baltimore-Washington international airport in a rented van and flown to Iraq.

By late summer 2003, almost 100 Warlocks had been deployed, according to an Army document that said IEDs were "increasing in number and complexity at an alarming rate." Another Navy jammer, originally designed to protect four-star flag officers, also began arriving in the theater -- first six, then 30 and eventually 300.