The Obama administration has moved swiftly to end controversial practices that tarnished America's international reputation and undermined its moral authority. But in doing so, it has raised new questions about how the United States will prosecute and punish terrorists in future, and where and under what conditions it will send them if they are not considered to be a major threat.

These new questions underscore an old dilemma facing countries targeted by terrorists: Can attacks be prevented under existing systems of law and justice that uphold standards hardcore terrorists themselves scorn and use to withhold information and avoid conviction?

In one of his first decisions after becoming U.S. president, Barack Obama signed orders to close the Guantanamo Bay detention center in Cuba within a year, review military trials of suspects, and ban torture and other coercive interrogation methods. He had earlier directed the Defense Department to suspend detainee trials and cease referring any new cases pending completion of the review.