The United States responded to the attacks by launching the War on Terror. Specifically, on October 7, 2001, it invaded Afghanistan to depose the Taliban, which had harbored al-Qaeda terrorists. On October 26, 2001, the U.S. enacted the Patriot Act that expanded the powers of U.S. law enforcement and intelligence agencies. Many countries followed with similar legislation. Under the Obama administration, the U.S. changed tactics moving away from ground combat with large numbers of troops, to the use of drones and special forces. This campaign eliminated much of al-Qaeda's most senior members, including a strike by Seal Team Six that resulted in the death of Osama Bin Laden in 2011.