LONDON — In his first public comment on the unfolding drama in Egypt, Benjamin Netanyahu, Israel's prime minister, worried aloud last week that the right analogy may be the Iranian revolution of 1979: "Our real fear is of a situation . . . which has already developed in several countries including Iran itself, repressive regimes of radical Islam."

The nonsectarian, nonparty protesters in Egypt who have driven President Hosni Mubarak to the brink of resignation, suggests Netanyahu, may lose control of their revolution just as the Iranians lost theirs to the ayatollahs.

The Muslim Brotherhood, an Islamist party that is particularly strong among the poor, might gain a dominant position in the new Egyptian government. The Muslim Brotherhood have always condemned the peace treaty that Egypt signed with Israel 32 years ago, so they serve as a sort of shorthand in Israeli politics for the nightmare scenario in which Egypt cancels the peace treaty.