Shane Harris and Matthew M. Aid write: The U.S. government may be considering military action in response to chemical strikes near Damascus. But a generation ago, America’s military and intelligence communities knew about and did nothing to stop a series of nerve gas attacks far more devastating than anything Syria has seen, Foreign Policy has learned.

In 1988, during the waning days of Iraq’s war with Iran, the United States learned through satellite imagery that Iran was about to gain a major strategic advantage by exploiting a hole in Iraqi defenses. U.S. intelligence officials conveyed the location of the Iranian troops to Iraq, fully aware that Hussein’s military would attack with chemical weapons, including sarin, a lethal nerve agent.

The intelligence included imagery and maps about Iranian troop movements, as well as the locations of Iranian logistics facilities and details about Iranian air defenses. The Iraqis used mustard gas and sarin prior to four major offensives in early 1988 that relied on U.S. satellite imagery, maps, and other intelligence. These attacks helped to tilt the war in Iraq’s favor and bring Iran to the negotiating table, and they ensured that the Reagan administration’s long-standing policy of securing an Iraqi victory would succeed. But they were also the last in a series of chemical strikes stretching back several years that the Reagan administration knew about and didn’t disclose.

U.S. officials have long denied acquiescing to Iraqi chemical attacks, insisting that Hussein’s government never announced he was going to use the weapons. But retired Air Force Col. Rick Francona, who was a military attaché in Baghdad during the 1988 strikes, paints a different picture.

“The Iraqis never told us that they intended to use nerve gas. They didn’t have to. We already knew,” he told Foreign Policy.

According to recently declassified CIA documents and interviews with former intelligence officials like Francona, the U.S. had firm evidence of Iraqi chemical attacks beginning in 1983. At the time, Iran was publicly alleging that illegal chemical attacks were carried out on its forces, and was building a case to present to the United Nations. But it lacked the evidence implicating Iraq, much of which was contained in top secret reports and memoranda sent to the most senior intelligence officials in the U.S. government. The CIA declined to comment for this story.

In contrast to today’s wrenching debate over whether the United States should intervene to stop alleged chemical weapons attacks by the Syrian government, the United States applied a cold calculus three decades ago to Hussein’s widespread use of chemical weapons against his enemies and his own people. The Reagan administration decided that it was better to let the attacks continue if they might turn the tide of the war. And even if they were discovered, the CIA wagered that international outrage and condemnation would be muted. [Continue reading…]