Sully the service dog of former U.S. President George H.W. Bush lays in front of Bush's casket as it lies in state inside the U.S. Capitol Rotunda on Capitol Hill in Washington, U.S., December 4, 2018. (Reuters/Jonathan Ernst/File Photo)
WASHINGTON (Reuters) - Lifting his thick paw to shake, former President George H.W. Bush's service dog took an oath to serve at Walter Reed National Medical Center on Wednesday, embarking on a new job helping disabled American veterans and active-duty service members.