Why the Ayatollah thinks he won

Since the accord was announced last summer, Mr. Khamenei and his elite military unit, the Islamic Revolutionary Guard Corps, have moved to solidify their hold. As international sanctions against Iran have slackened, the ayatollah and his core allies have expanded the Iranian military and pursued new business opportunities for the companies and foundations that finance the regime’s key ideological cadres. Iran has continued to fund and arm its major regional allies, including the Assad regime in Syria, the Lebanese militia Hezbollah and Houthi rebels in Yemen—all of which are at war with America’s regional partners—and the regime has continued to test and develop ballistic missiles. The government has also stepped up arrests of opposition leaders and political activists.

Mr. Khamenei has been deeply involved from the start with his country’s talks with the U.S. After the U.N. Security Council imposed tough sanctions on Iran in 2010, he became alarmed by the drain on Tehran’s finances. In 2012, he backed secret talks in hopes of relieving the crippling financial pressure. A collapse in global oil prices made Iran even more vulnerable. As the talks evolved into public negotiations with the U.S. and its partners, Mr. Khamenei instructed his representatives to ensure that Iran could keep the major infrastructure of its nuclear and military programs.

Today, the 77-year-old ayatollah—who reportedly suffers from cancer—is seeking to cement his legacy and to shape the political transition that will occur once he is gone. The nuclear agreement provides him with the building blocks to do that, and for now, at least, Mr. Khamenei and his allies look to be the deal’s big winners. The next U.S. administration is likely to face an unhappy choice: to continue to work with Iran or to challenge an increasingly entrenched supreme leader and his Revolutionary Guard.