The United States has spent more than $8 trillion on the War on Terror since 2001, a continuing conflict that has resulted in more than 900,000 deaths worldwide, according to research conducted by Brown University.
The War on Terror started as a result of the September 11, 2001 terror attacks. In late August, the United States withdrew troops from Afghanistan and the Taliban regained control over the country for the first time since 2001. Yet the War on Terror isn't over yet. There are still 2,500 troops in Iraq until at least the end of this year, for example. And the United States has involvement in the Syrian civil war, a country where there are 900 U.S. troops.