RICHARD NIXON'S own postmortem on his stewardship in international affairs was, unsurprisingly, fond and flattering.It was apparent while he was in the White House that he enjoyed treading on the global stage - especially in crises - and, indeed, that he believed this was where his special talents lay. The same relish was no less evident in his David Frost interview the other evening. It was an exercise in nostalgia, and a not unimpressive one at that.

As Mr. Nixon recalls it, he dealt coolly and knowledgeably with the Russians and Chinese and, in different episodes, saved Israel and Egypt and Pakistan as well. We would have liked him to test his rather mellow image of detente, which he clearly regards as his masterwork, against the need to call nothing less than a nuclear alert in order to get a "message" to the Kremlin in the 1973 Mideast war. But never mind. Mr. Nixon is entitled to as much time in TV's sun as the free-enterprise system is prepared to provide. Others, and perhaps Mr. Nixon himself in his memoirs, will be able to make further contributions to the writing of history. Moreover, on the matter most immediately titillating to us gossips in Washington - his elaborate putdown of his adviser Henry Kissinger - we will surely have Mr. Kissinger's own response in time.

Was Mr. Nixon's performance in international diplomacy so formidable or unique - or redeeming - as it pleases him now to indicate in his own effusive way? The sharp tailing off of the television-viewing audience is part of the answer. Watching the fallen President, we were left bemused and not entirely persuaded by his accounting. Perhaps it is one's latter-day awareness that detente did not turn out to be as successful and self-sustaining an enterprise as many had hoped. But it is also one's sense that Mr. Nixon, though more genial in manner, was no less combative and contrived in purpose. He is not exactly your archetypal, mellowed elder statesman, confidently reflecting on a record acknowledge to incorporate a certain human frailty. Rather, he remains the partisan - one might almost say desperate - defender of that record. And this ggives to his nostalgia a hard, self-serving edge.