Think of normalized relations with the United States as the big prize. Who gets to deliver it? One thing is certain: Iran’s ruthless usurpers are determined to ensure reformists are never in a position to claim the breakthrough.

That at least is the view of Mohsen Mahmoudi, a 34-year-old conservative cleric I ran into at a post-electoral rally for President Mahmoud Ahmadinejad and got to know over the ensuing week.

Rightist yet drawn to America, a card-carrying Basij militiaman from the University of Qom, a prayer leader at an Islamic cultural center in north Tehran, Mahmoudi backs the regime’s brutal clampdown but concedes there will be a cost.

“This is going to cause a huge gulf between generations,” he told me. “I was talking to a...