AMERICANS do not keep their presidents in limbo for long. Take the case of Richard Milhous Nixon. Roughly 10 years ago, President Nixon resigned his office in utter disgrace over the Watergate scandal. Today he has chalked up a long list of well-received books, articles, and television appearances; he is a much-sought-after speaker at Republican fund-raisers and other forums; and he is consulted regularly by President Reagan and others for his views on foreign policy.
''It's an astonishing comeback,'' says presidential scholar Thomas E. Cronin of Colorado College. ''Historians do not rate Mr. Nixon well because of the unforgivable stains on the presidency and the fact that he weakened the institution through his excesses of power. But aside from Watergate, his achievements with respect to detente and other foreign policies would have to be rated high.''
Even the press, which always had an adversarial relationship with Nixon and for which Nixon has had little liking, has jumped on the comeback wagon. Last week Nixon was the featured speaker at a luncheon meeting of the American Society of Newspaper Editors (ASNE). The hall was crowded and the audience of some 900 writers and editors attentive and respectful.
Relaxed, self-assured, articulate, Nixon gave a masterly talk about Soviet-American relations and US foreign policy. He spoke without notes. He answered questions - about American politics, Spiro Agnew, Central America - with ease, and even humor. Asked about the lessons of Watergate, he responded that ''I have covered the subject as well and as honestly as I can.''
''I think 10 years of Watergate is enough, and as far as I am concerned I am going to talk about the future, not the past,'' he told the gathering.
Would he draw up an ''enemies list'' today? ''I did not make it up,'' said Nixon. But, he added, he participated in it as president in a ''controversial period.'' ''As far as I am concerned now, and speaking for this audience, I have no enemies in the press whatever.''
At the end of his appearance, applause for the former President, though not an ovation, was appreciative and sustained. Many approving comments could be heard. ''Take away Watergate,'' said one Midwestern newspaper editor, ''and he's better than the present incumbent.''
Since his resignation in August 1974, the former President has written four books and traveled to more than a dozen countries, including the People's Republic of China. His articles on foreign policy appear in the national press frequently.
As far as the whole, sordid Watergate cover-up conspiracy is concerned, Nixon has never directly said he was guilty. Last month, CBS News aired a lengthy interview with Nixon in which he essentially repeated statements he had made in the David Frost interviews in 1977, when he said, ''I impeached myself.'' Asked on this occasion by interviewer Frank Gannon whether he should apologize for Watergate, he replied: ''There's no way that you could apologize that is more eloquent, more decisive, more finite, which would exceed resigning the presidency of the United States. That said it all.''
The Nixon resurgence seems to reflect a theme in the American character: to give a man the benefit of the doubt and let him put his failings behind. Other presidents who have left office under a cloud have also been rehabilitated in the public mind. Recently Washington paid honor to Harry Truman, who had a low 26 percent approval rating when he departed the White House. The Eisenhower presidency has been revised upward. Herbert Hoover, held responsible for the Great Depression, also won the public's esteem as an elder statesman after serving on presidential commissions in the 1950s and '60s. A Carter comeback has been slow in coming, but even President Carter has begun to reappear.
''When time passes, a president gets viewed in more perspective,'' says political scientist James Sundquist, of the Brookings Institution. ''The Nixon record was not all black. He had real accomplishments which are not obscured by the scandals. No one will forgive the 'enemies list' mentality and the abuses of power, but foreign policy has to be regarded and here the credit is largely his.''
''He can never put Watergate behind,'' comments Stephen Wayne, a presidential scholar at George Washington University, ''but he shows a kind of resiliency and determination, an incredible perseverence, that is also part of the Nixon character. He's a smart man. He wants to have an impact on policy, and he waited until the fervor of Watergate died down and there was another Republican administration which is more appreciative of what he did.''
''There's no reason why he shouldn't be consulted on foreign policy,'' says Dr. Cronin, author of ''The State of The Presidency.'' ''We shouldn't turn our back on him completely. But we need to remember his errors as vividly as his triumphs. He was flawed in character.''
To those concerned that the lessons of Watergate will be forgotten, historians and political experts note that the institutional and legal reforms taken in the wake of that scandal are likely to last a long time. These include new public-disclosure laws and provision for a special prosecutor or ''independent counsel'' when ranking executive officials are suspected of wrongdoing. Such a counsel is now examining the finances of Edwin Meese III in connection with his appointment as US attorney general.
Mr. Sundquist suggests that it was more than five decades before the nation got over the scandals during President Grant's time or the Teapot Dome scandals of the Harding administration. ''Politicians will be aware of the Watergate affair for a long time and will not make the same mistakes,'' he says. ''It will be 50 years before a president accumulates tapes. . . . The impetus for reform has died, but the new laws are a permanent part of the institutional system.''
As Nixon was leaving the ASNE luncheon at the Sheraton-Washington Hotel last week, editors and others pressed around him, still peppering him with questions. A number of people asked for his autograph. It was all a marked contrast to the time more than a decade ago when he told newspaper editors, ''I am not a crook.''