Why did the united states invade iraq in 2003? the bush administration believed that iraq had wmd. iraq had threatened to attack the united states. iraq had trained the terrorists that attacked the united states. the united nations asked for from american troops.

The United States invaded Iraq in 2003 because the Bush administration believed that Iraq had WMD.

Explanation:

The Iraq War was started by the United States and the United Kingdom in March 2003, with other countries also supplying troops.

The war can be divided into two phases. The first phase was the invasion in which a multinational force dispelled Saddam Hussein's rule. This phase lasted from 20 March 2003 to 1 May 2003.

The aim of the coalition was to overthrow the Saddam Hussein regime, which was oppressing the Iraqi population, supporting international terrorism and developing, possessing and deploying weapons of mass destruction. To date, such weapons have not been found, nor has a connection with Al Qaeda been demonstrated.  

The subsequent phase, which continues today, consists of a nation-building program, the building of a new Iraq by the coalition force. However, this phase is plagued by large-scale revolts that are so serious that it is referred to as a civil war.