(CBS News) Meir Dagan has been described as "hard-charging" and "stops at nothing." For more than eight years, Dagan made full use of those qualities as chief of Mossad, Israel's intelligence agency, where he focused on keeping Iran from developing a nuclear weapon. When that job ended, Dagan did something unheard of for an ex-Mossad chief: he spoke out publicly, voicing opposition to Israel launching preemptive airstrikes against Iran's nuclear facilities anytime soon. Dagan believes the Iranian regime is a rational one and even its president, Mahmoud Ahmadinejad - who has called for Israel to be annihilated - acts in a somewhat rational way when it comes to Iran's nuclear ambitions. Lesley Stahl reports.