Iraq and weapons of mass destruction concerns the Iraqi government's use, possession, and alleged intention of acquiring more types of weapons of mass destruction (WMD) during the presidency of Saddam Hussein. During his reign of several decades, he was internationally renowned for his use of chemical weapons against civilians and in the Iran-Iraq War. He also engaged in a decade-long confrontation with the United Nations and its weapons inspectors, culminating in the 2003 invasion by the United States with the stated purpose to keep him from developing WMD's. The United States, along with many other countries and intelligence experts, believed that Saddam Hussein already possessed WMD's, and must be prevented from building anymore. Hussein denied having any such weapons while at the same time refused to allow weapons inspectors unrestricted access to his countries various facilities. The United States and the United Nations came into conflict as various members refused to support a military solution to the crisis, and the United States and the "Coalition of the Willing" overthrew Saddam Hussein in the spring of 2003. Great controversy emerged when no stockpiles of such weapons were found, leading to accusations that the United States, and in particular its President George W. Bush had lied about Iraqs weapons in order to justify an invasion of the country, supposedly for various political or monetary ends. As of June 21, 2006, declassified documents show that over 500 chemical weapons built before 1991 have been recovered in Iraq, though no post 1991 stockpiles have been found. Various leftover weapons components from the 1980's and 1990's have also been found, and most weapons inspectors do not believe that the WMD program proceeded after the early 1990's, though various theories as to their fate continue to be put foreword.