Secretary of State Hillary Rodham Clinton is finding that her job description is dissolving under her feet, leaving her with only a vestige of the power she must have thought she acquired when she signed on to be President Obama’s chief Cabinet officer. Since her designation: • Vice President Biden has moved vigorously to stake out foreign policy as his turf. His visit to Afghanistan, right before the Inauguration, could not but send a signal to Hillary that he would conduct foreign policy in the new administration, leaving Hillary in the role of backup. • Richard Holbrooke, the former Balkan...