President Obama on his second full day in office ordered the closing of the Guantánamo detention camp within a year. The facility at the U.S. Naval Station in Cuba has been controversial ever since President George W. Bush decided in late 2001 to use it to hold suspected enemy combatants captured in Afghanistan and elsewhere. Both Obama and Republican candidate John McCain promised during the presidential campaign to close the facility if elected. But that poses many difficult issues about the camp's remaining 241 prisoners. The government wants to send many to other countries -- with few takers so far -- but worries that some may resume hostile activities against the United States. Some may be brought to the U.S. for trial, but those prosecutions would raise a host of uncharted legal issues. Meanwhile, opposition already has surfaced to any plans for housing detainees in the United States. And human-rights advocates worry the Obama administration may continue to back some form of preventive detention for suspected terrorists.