GENEVA — All senior U.S. officials and CIA agents who authorized or carried out torture like waterboarding as part of former President George W. Bush's national security policy must be prosecuted, top U.N. officials said Wednesday. It's not clear, however, how human rights officials think these prosecutions will take place, since the Justice Department has declined to prosecute and the U.S. is not a member of the International Criminal Court. Zeid Raad al-Hussein, the U.N. high commissioner for human rights, said it's "crystal clear" under international law that the United States, which ratified the U.N. Convention Against Torture in 1994, now has an obligation to ensure accountability.