A decisive event that reshaped his administration was the terrorist attacks on September 11, 2001, resulting in the start of the war on terror and the creation of the Department of Homeland Security. Bush ordered the 2001 invasion of Afghanistan to overthrow the Taliban, destroy al-Qaeda, and capture Osama bin Laden. He signed the Patriot Act to authorize surveillance of suspected terrorists. Bush also ordered the 2003 invasion of Iraq on the belief that Saddam Hussein's regime possessed weapons of mass destruction (WMDs); although no WMDs were ever found in Iraq, Hussein was nevertheless overthrown and captured by U.S. forces. Bush also signed the Medicare Modernization Act, which created Medicare Part D.
Bush was re-elected president in 2004, defeating Democrat John Kerry and winning the popular vote. During his second term, Bush reached multiple free trade agreements. He appointed John Roberts and Samuel Alito to the Supreme Court. He sought major changes to Social Security and immigration laws, but both efforts failed in Congress. Bush was widely criticized for his handling of Hurricane Katrina and the midterm dismissal of U.S. attorneys. 