President Obama signed an executive order Monday that will create a formal system of indefinite detention for those held at the U.S. military prison at Guantanamo Bay, Cuba, who continue to pose a significant threat to national security. The administration also said it will start new military commission trials for detainees there. The announcements, coming more than two years after Obama vowed in another executive order to close the detention center, all but cements Guantanamo Bay's continuing role in U.S. counterterrorism policy. The executive order recognizes the reality that some Guantanamo Bay detainees will remain in U.S. custody for many years, if not for life. Activists on either end of the debate over closing the prison cast the announcement as a reversal. It is virtually impossible to imagine how one closes Guantanamo in light of this executive order," said Anthony Romero, executive director of the American Civil Liberties Union. "In a little over two years, the Obama administration has done a complete about-face." Recent legislation now makes it extremely difficult to transfer any detainee out of Guantanamo Bay even if he is believed to be no threat.