The odds are on J. Danforth Quayle, oft-reviled, much joked about, becoming the next president of the United States. As the current vice-president, he automatically succeeds to the most powerful political office in the world if anything should happen to George Bush. And since Bush - who is 68 - collapsed at the Tokyo summit in January 1992, the state of the President's health has once again focused attention on Dan Quayle. As Bob Woodward and David S. Broder also point out in this presidential election year, since 1952 all but one elected vice-presidents have gone on to claim their parties' nominations for president, and five of the last presidents served as vice-president. "Washington Post" journalists Woodward and Broder investigate the man, his career and his influential wife Marilyn in this assessment, and ask "what if Quayle becomes President?" Bob Woodward's books include "The Final Days" and "All the President's Men" (with Carl Bernstein). He is assistant managing editor of "The Washington Post". David S. Broder is the paper's leading political columnist.