(…) Here are the two documented retreats:
● In July 1988 Ayatollah Ruhollah Khomeini “drank the cup of poison,” as he put it, and agreed to end the Iraq-Iran war. He accepted a U.N.-sponsored truce but only after eight years of brutal fighting, Iraqi rocket attacks on Iranian cities and the use of poison gas against Iranian troops. Khomeini’s decision followed the shooting down of an Iranian civilian airliner on July 3 by the USS Vincennes — unintended but a demonstration of overwhelming American firepower in the Persian Gulf.
● In the fall of 2003 Ayatollah Ali Khamenei’s regime halted its nuclear weapons program because of “international pressure,” according to a 2007 U.S. National Intelligence Estimate. The decision came after the March 2003 U.S. invasion of Iraq, which the Iranians apparently feared was the prelude to an attack on their soil. The Iranians also agreed in 2003 to start talks with European nations on limiting their enrichment of uranium — beginning the haggling that continues to this day.
Two other examples are less obvious, but they illustrate the same theme of rational Iranian response to pressure. In both cases the trigger was a strong back-channel message from the United States:
● In March 2008, Iran restrained its Shiite allies in Iraq after a U.S. warning about shelling the Green Zone. The Mahdi Army had been firing heavy rockets and mortars into the enclave, causing rising U.S. casualties. Gen. David Petraeus, then U.S. commander in Baghdad, sent a message — “Stop shooting at the Green Zone” — to Gen. Qassem Suleimani, head of the Quds Force. The intermediary was Iraqi President Jalal Talabani, who had close relations with both generals. The shelling tapered off.
● Last month, Iran toned down its threats to close the Strait of Hormuz after a U.S. back-channel warning that any such action would trigger a punishing U.S. response. The private message paralleled a public U.S. statement: “The United States and the international community have a strong interest in the free flow of commerce and freedom of navigation in all international waterways.” Iranian Foreign Minister Ali Akbar Salehi subsequently offered reassurance: “Iran has never in its history tried to prevent, to put any obstacles in the way of this important maritime route.”
The Iranians’ behavior in negotiations, too, has seemed to wax and wane based on their perception of the West’s seriousness. When Russia and China supported U.N. sanctions in 2010, the Iranians got nervous. When India and China reduced oil purchases recently, Tehran took notice.