<human>:  Why did the United States invade Iraq in 2003?
<bot>: The United States invaded Iraq in 2003 because Saddam Hussein had weapons of mass destruction. After the 9/11 attacks, the Bush administration believed that Saddam Hussein was a threat to the United States. The Bush administration believed that Saddam Hussein had links to Al Qaeda and that he could use these weapons of mass destruction against the United States.