One senior intelligence official argued that as Mr. Bush prepared to leave office, the Iranians were already so close to achieving a weapons capacity that they were unlikely to be stopped.New York Times
Others disagreed, making the point that the Israelis would not have been dissuaded from conducting an attack if they believed that the American effort was unlikely to prove effective.
(The same reporter, David Sanger, also writes on The Worst Pakistan Nightmare for Obama, such as: what happens when [the Pakistani military] move the [nuclear] weapons. The United States feared that some groups could try to provoke a confrontation between Pakistan and India in the hope that the Pakistani military would transport tactical nuclear weapons closer to the front lines, where they would be more vulnerable to seizure. Indeed, when the deadly terror attacks occurred in Mumbai in late November, officials told me they feared that one of the attackers’ motives might have been to trigger exactly that series of events.)