Israel may succeed in taking out Iran’s air defenses, ballistic missiles and much of its nuclear program. But that would still leave hundreds of thousands in the military, the Revolutionary Guard and forces known as the Basij, who played a key role in quashing waves of anti-government protests in recent years.

Airstrikes continued for a sixth day Wednesday amid the most intense faceoff in the history of the Israel-Iran conflict. The confrontation that began Friday, when Israel launched an air campaign targeting Iran’s nuclear program and its military leaders,