<human>:  Why did the US invade Iraq?
<bot>: The US invaded Iraq because Saddam Hussein was a threat to the US. Saddam Hussein was a brutal dictator who had used chemical weapons against his own people. He also had ties to terrorist organizations such as Al Qaeda. In addition, he had been developing weapons of mass destruction (WMD) that could be used against the US and other countries. After the 9/11 attacks, the US decided that Saddam Hussein was a threat to the US and that he needed to be removed from power.