Of Gerald Ford it can be said that nothing so became him as the way he began his presidency and nothing so becomes him as the way he ends his presidency.

After serving for 2 1/2 years under extraordinary circumstances and then suffering one of history's closest defeats, he completes his term with no sense of rancor or regret. He exudes good will, seems genuinely at peace with himself, and strongly believes he leaves behind a better America.

"By any standard," he says, "the best achievement of this administration is the fact that we found a nation that was tormented, divided, angry with one another, and I think we have reunited the people."

Whatever his hurt over his loss to Jimmy Carter, Ford now gives the impression of looking forward to leaving Washington after a generation of public life. He had planned on retiring anyway after the 94th Congress, he recalls, so he'll be finishing his political career only 17 days later. In fact, he had announced his intentions before the series of events that stunned the nation and propelled him, unelected, into the presidency: Spiro T. Agnew's resignation, Watergate and impeachment, Richard M. Nixon's fall.

As he reflects on those times, Ford sees a marked charge in the nation today. the spirit is healthier, he thinks, and will continue to be so: the tone is more even, the discourse more civil. Even the political debates of 1976 were, in his view, "more reasonable." Labor-management disputes "are much more nature." And the atmosphere on campuses is notably improved.

"I think as an ex-President I will be welcomed on the university and college campuses," he says," and will spend some time there. That is a lot different than it was in 1973-74."

In short, Gerald Ford, truly our only accidential President, prepares to leave the White House certain that he bequeaths a more wholesome national climate. He speaks kindly of his successor, wishes him well, thinks Carter has "unique opportunities" to fashion "great success."

Specifically, Ford sees Carter facing immediate decisions of critical importance intenationally and domestically. Conditions in both Souther Africa and the Middle East are now at what Ford believes to be "a very crucial breakthrough situation." By that he means: "Both of those areas are on the brink of either success or potential catastrophe. It is almost the situation that hasn't occurred in the past and may no occur in the future. They are just at that right point."

The same challenge exists on the nation's economic policy. There, too, decisions must be made by the next President in the immediate weeks and months to come.As Ford puts it:

"Domestically, my feeling is we have made a lot of headway in coming out of the recession, but we are at a very crucial point where great skill, good judgment can make the difference as to whether we lose the progress we have made in inflation and tip the balance one way or another in order for some quick success in unemployment."

Ford is not, by nature, introspective. In these last days in the White House he conveys a feeling of relaxed good nature. He speaks openly and easily, laughs frequently, seems to be enjoying himself.

His Oval Office is bright and cheery, far removed from the tense place of secret tapes and conspiracies during the darker moments of the Nixon years.

A fire crackles, and Ford delights in showing visitors a new carpet, installed over the holiday period. It was woven in America, he says with a touch of pride. He likes it. Then, a bit ruefully, he points out that it may not find favor with the next occupant.

He gets up and leads the way to the small adjoining office where he has done most of his presidential work. It looks out over the pool, he says - Ford's pool, it undoubtedly will be called in later years, just as the balcony overlooking the gardens and the Ellipse bears the name "Truman's Balcony." It's been a good place to work, the President says. The walls to that office are Bare now; all the paintings have been removed, and only the framing hooks remain. Ford notes that without a trace of wistfulness or regret.

All this seems entirely normal, free of the complexities associated with people of great power. And Ford talks about his presidency in the same even, calm, almost detached manner. Yet he does offer personal insights on some of the most troubling aspects of national life.

Ford came to power at a time of a great moral crisis. During his brief presidency, the public became aware of even more abuses of political power. In the Congress, accounts of corruption continue to surface. In the executive agencies, and the presidency itself, we now know more about murder and assassination plots from earlier administrations.

When asked about such questions and their ethical implications for government, Ford answers by saying:

"I would be dishonest to say that I was not disappointed with some of the things that I have seen, read about, heard about in the Congress in the last two years. I was oblivious to them when I was on the Hill.

"You heard rumors and things of that sort. But I just didn't know they went on to a degree that has been revealed. I certainly didn't know of Watergate because I was told differently, and I believed what I was told.

"When you get over my lack of knowledge, let me put the affirmative twist on it. I happen to think that the overwhelming majority of people I served with in the Congress, Democrat, Republican, House and Senate, are honest, hard-working people. And I believe the same about those who have been in the executive branch of the government. It is tragic tht few here and there created a very bad impression as far as the morals of government are concerned."

As for assassination plots in previous administrations, yes, he says, "I am sure it did take place in the past without identifying who or where." And: "As far as I know nothing comparable to that has taken place in this administration."

As far as the possibility of such future actions - well, the President thinks, his successors should, in governmentese, keep their options open.

"In the atmosphere, in the circumstances we live in today, I don't think it [assassinations] should take place," he says. "But I can envision World War III, where the life or death of the United States might depend upon some very strong action.

"I think the only one who can make that decision at that time is the person who has to look at the alternatives. All I am saying is, he might have to be that tough because, you know, moral decisions can be two-sided.

Another question draws less of a response. It's about Nixon. Yes, he acknowledges, the pardon was one of his most difficult decisions, and he was aware of potential political ramifications. "They were harmful in the election, no question about it."

But he doesn't dwell on it, says he hasn't brooded about the pardon or related questions. He hasn't had second thoughts about obtaining a concession of guilt from Nixon. Nor has he been troubled by the question of seeing others serve prison terms for lesser offenses, than the former President.

"Former President Nixon is the only President out of 38 who ever resigned," Ford says. "That is a pretty black mark on anybody's lifetime. I don't think you can really equate that with an actual prison term."

And that is that. He fully realizes as he says, that "we were in real trouble across the spectrum" when he took office and that "it got worse in some respects." But that is behind us now; now, "we are on the way up in many, many ways."

That, at least, is his personal assessment, the legacy he would like to be credited with leaving. When he says, "I am an optimist about what is going to happen in the future," you are sure he really means it.

When he is reminded that history hasn't been too kind to our ex-Presidents, Gerald R. Ford has a ready reply.

"I hope I am an exception," he says.