From a Washington Post story of Dec 30, 2002 by Michael Dobbs
http://www.washingtonpost.com/ac2/wp-dyn/A52241-2002Dec29
Among the people instrumental in tilting U.S. policy toward Baghdad during the 1980-88 Iran-Iraq war was Donald H. Rumsfeld, now defense secretary, whose December 1983 meeting with Hussein as a special presidential envoy paved the way for normalization of U.S.-Iraqi relations. Declassified documents show that Rumsfeld traveled to Baghdad at a time when Iraq was using chemical weapons on an "almost daily" basis in defiance of international conventions. […]
The U.S. tilt toward Iraq was enshrined in National Security Decision Directive 114 of Nov. 26, 1983, one of the few important Reagan era foreign policy decisions that still remains classified. According to former U.S. officials, the directive stated that the United States would do "whatever was necessary and legal" to prevent Iraq from losing the war with Iran. […]
[By Nov 1983,] intelligence reports showed that Iraqi troops were resorting to "almost daily use of CW" against the Iranians. But the Reagan administration had already committed itself to a large-scale diplomatic and political overture to Baghdad, culminating in several visits by the president's recently appointed special envoy to the Middle East, Donald H. Rumsfeld. […]