He covered the Watergate investigation as well as the impeachment proceedings.
The Watergate investigation showed that Nixon operatives had poured illegal campaign funds into the race.
Butterfield's revelation of the taping system transformed the Watergate investigation yet again.
We have succeeded so far in avoiding this impression, I believe, because of the lessons learned during the Watergate investigation.
Closer to our own day, many of us still remember the "dirty tricks" of the 1972 campaign made famous by the Watergate investigation.
But in retrospect, some disenchantment may have been planted during the Watergate investigation itself.
The Watergate investigation led to the resignation of the President.
The only occasion in living memory when it failed was during the Watergate investigation.
The fourth was in Washington, where he tried to keep the agency from self-destructing during the years of the Watergate investigations, 1973 to 1975.
Should that crisis be at hand, he said today, the nation "does not need another Watergate investigation."