<human>:  Why did the US invade Iraq?
<bot>: The US invaded Iraq because it was a threat to US national security. The US government believed that Saddam Hussein was developing weapons of mass destruction and that he was attempting to acquire nuclear weapons. The US government also believed that Saddam Hussein was involved in the September 11 attacks. The US invaded Iraq because it wanted to remove Saddam Hussein from power and stop him from developing weapons of mass destruction.