None of the tests involved a Scud, a target that is particularly difficult to hit because of its high speed and erratic flight path.
"The PAC-3 missile has been retrofitted into a system that is basically '70s technology," said Cirincione, now an analyst with the Carnegie Endowment for International Peace.
"We may need a brand-new system. But we'll never know that until you realistically test the Patriot."
Military planners argue that until airborne laser weapons are deployed -- years from now, at best -- the Patriot represents the best missile-defense option for general combat.
The Army's enthusiasm for the Patriot has been bolstered by the system's seemingly perfect record of nine life-saving missile kills in the Iraq war.
But skepticism of such claims is running high because of the Patriot's history of exaggerated accomplishments.
In the 1991 Gulf War, the system also seemed to perform almost flawlessly -- at first.
The Army said that Patriots intercepted 45 of the 47 Scuds targeted. But MIT's Postol analyzed video footage of 28 of those cases and found that not a single Scud warhead was destroyed. In fact, the Patriots often missed the target by hundreds of meters. Such misses were apparently claimed as hits, he said, if the crudely targeted Scuds struck uninhabited areas.
"It's as if you were sitting at home viewing a Scud attack on television, clapped your hands, and then if there wasn't major damage, you claimed to have intercepted it," Postol said.
His results were confirmed by a House Governmental Operations Committee study led by Cirincione in 1992.
"When we scrubbed the data, it turned out that the best evidence supported successful intercepts of between zero and four Scuds," Cirincione said.
Ultimately, the Army reduced its claims from 45 to 24 warhead kills.
So far, the only evidence that a Patriot shot down an Iraqi missile in the current conflict is a photo of an Al Fatah short-range ballistic missile recovered in the Kuwaiti desert.
The photo alone cannot verify that the missile's warhead was destroyed, experts said. Nor can it prove the missile had been intercepted rather than malfunctioning on its own, experts said.
Military officials declined to release details about the nine reported intercepts.
Even if the claim of a perfect Patriot record in the Iraq war can be verified, Postol noted that all of its kills were of short-range weapons such as Al Fatah, Al Samoud or Ababil-100 missiles that experts say are far easier to hit than Scuds.
"Given the history of lying [about the Patriot], the only way I would accept their claims is to see their data," Postol said.
