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NEW YORK — In his last month as head of the International Atomic Energy Agency, Mohamed ElBaradei finds himself at the explosive crux of the world’s nuclear politics, ferrying messages between the Obama administration and Tehran. “They are talking through me,” he says.

Roger Cohen

Talking is something, even through a mediator, given all the poisonous U.S.-Iranian history, but time is short. President Obama’s Iran outreach is on the line in the days before ElBaradei departs on Nov. 30. It’s critical that Obama succeed or a futile confrontation-sanctions scenario will be locked in. Any vestigial hopes for a more peaceful Middle East will recede.

Protesters, Iran’s brave campaigners for a freer and more open country, are chanting,...