::In addition, Nixon's impeachment course was not simply political rhetoric, it was a near inescapable reality.  
 :::From the New York Times (Aug. 8, 1974), "His chances of being acquitted were almost hopeless. Senator Barry, Goldwater, the Arizona conservative who was the Republican Presidential candidate in 1964, told him that he had no more than 15 votes in the Senate, far short of the 34 he needed to be sure of escaping conviction. Members of his own staff, including Gen. Alexander M. Haig Jr., the White House chief of staff, strongly recommended that he step down in the national interest." 
 ::He wouldn't have resigned if he thought he could beat it. 
 :::From Nixon's resignation speech: "Throughout the long and difficult period of Watergate, I have felt it was my duty to persevere  to make every possible effort to complete the term of office to which you elected me. In the past few days, however, it has become evident to me that I no longer have a strong enough political base in the Congress to justify continuing that effort." 
 ::So you ask, "Why make mention of him if he wasn't impeached?" In all but official action, he was. And for that reason, and the reasons I mention above, he should be mentioned in the article alongside Clinton and Johnson.