In the ebb and flow of the watchdog role over the last two centuries, we are reaching a moment of diminution by dilution. The celebrity of Woodward and Bernstein was followed by the success of 60 Minutes, in which correspondents Mike Wallace, Morley Safer, Harry Reasoner and Ed Bradley became stars in their own reports. People tuned in to see who Mike, Morley, Harry, and Ed would catch this week.