Greigg served as the deputy chairman of the
Democratic National Committee from 1970 to July 1972. It was in that position that Greigg found himself at the genesis of the Watergate scandal in the early morning hours of June 17, 1972. In the office of Greigg's personal secretary, in DNC headquarters at the Watergate complex, D.C. police officers first confronted burglars carrying eavesdropping devices. Awakened early that morning by a call from a D.C. policeman and informed that his offices had been burglarized, Greigg asked, "did you catch the kids?" The officer responded, "no, sir, these men we arrested were in business suits." Greigg called DNC Director
Lawrence O'Brien, and told him that "all hell had broken loose." In July 1972, Greigg moved from his party position to a similar role in the 1972 presidential campaign of
George McGovern. He also served as director of the Lawrence F. O'Brien Center at Dag Hammarskjold College in 1972. ==Congressional Budget Office==