Mohammed Elbaradei , the U.N.'S point man on nuclear proliferation, plans to jet to Iran this week to urge its government to cooperate with a U.N. probe into its nuclear program. The Security Council, which relied in part on information the U.S. extracted from a single laptop computer that purportedly belonged to an Iranian engineer, gave Iran until April 28 to comply with the investigation. But a senior Bush Administration official tells TIME that there remain "substantial uncertainties" about the state of Tehran's nuclear program. "Iran is a very hard target," he concedes. "The truth is, if a country is going to try and pursue a nuclear program, they are going to try and do it in a way that's free from public view."
Such qualms within the Administration worry some outside it, who are starting to sense déjà vu. Jane Harman, the top Democrat on the House Intelligence Committee, notes similarities with Iraq. "We've seen this movie before," she says. Referring to a famous Iraqi informant known as Curveball, who proved to be an untrustworthy source, Harman asks, "Are we sure that Curveball or someone like Curveball isn't starring in this film too?"
A senior U.S. intelligence official insists the intel on Iran is solid. "What we've got is good," he says. Washington, the official says, has learned its lesson after being so wrong about Iraq's weapons program. But, he notes, "we also know what we don't know. We know what the gaps are."
In the meantime, Iran shows little sign of compromise. Tehran still insists it's interested in nuclear technology only for energy, not weapons. Its neighbors were not soothed, however, when Iran tested three advanced missiles last week.