Why did the united states go to war against iraq in 2003? al-qaeda joined forces with saddam hussein. iraq was believed to have weapons of mass destruction. osama bin laden was thought to be hiding in iraq. the taliban took over in iraq after leaving afghanistan.

The United States went to war against Iraq in 200e because Iraq was believed to have weapons of mass destruction. Following faulty intelligence and poor decision making the United States decided to go to war in Iraq over the false belief that Iraq had weapons of mass destruction.