President Obama’s plans for reducing America’s nuclear arsenal and defeating Iran’s missiles rely heavily on a new generation of antimissile defenses, which last year he called “proven and effective.”
His confidence in the heart of the system, a rocket-powered interceptor known as the SM-3, was particularly notable because as a senator and presidential candidate he had previously criticized antimissile arms. But now, a new analysis being published by two antimissile critics, at M.I.T. and Cornell, casts doubt on the reliability of the new weapon.
Mr. Obama’s announcement of his new antimissile plan in September was based on the Pentagon’s assessment that the SM-3, or Standard Missile 3, had intercepted 84 percent of incoming targets in tests. But a re-examination of results from 10 of those apparently successful tests by Theodore A. Postol and George N. Lewis, being published this month, finds only one or two successful intercepts — for a success rate of 10 to 20 percent.