Why did the US and Britain lead an invasion of Iraq 2003?

The U.S. and Britain led the invasion of Iraq in 2003 primarily based on the belief that Saddam Hussein possessed weapons of mass destruction (WMDs) that posed a threat to global security. Additionally, the invasion aimed to remove Hussein from power, promote democracy in the region, and combat terrorism. Despite extensive claims regarding WMDs, no substantial stockpiles were found, leading to significant controversy and debate over the legitimacy of the invasion.