 The alliance has only been invoked once, for the invasion of Afghanistan after the September 11 attacks on the World Trade Center and The Pentagon.Following the September 11 attacks, in which eleven Australian citizens were also killed, there was an enormous outpouring of sympathy from Australia for the United States.Prime Minister John Howard became one of President George W. Bush's strongest international supporters, and supported the United States in the invasion of Afghanistan in 2001 and the invasion of Iraq in 2003.