"I felt, deep down, it was something I shouldn't do then. Interestingly enough, I feel it is something I think I should do now."

So said Reubin Askew to The Wall Street Journal in explaining why he chose to run for president this year and not in 1976. You will notice that he said nothing about how support for his candidacy was lacking in 1976 but is present this year.

You will notice, in fact, that for Askew, the decision was a highly personal one--almost a secular version of a religious calling for this deeply religious man. But in deciding for himself that he ought to be president, he is, with one or possibly two exceptions, like his fellow candidates. They are their own bandwagons.

The latest one to become a voice in the political wilderness is George McGovern. The 1972 Democratic nominee virtually has announced his candidacy. And while his credentials for the race are obvious, and his determination to widen the debate admirable, he nevertheless already has lost the presidency once (by a landslide) and, later, his South Dakota seat in the Senate. Like the others in the race, with the exception of President Reagan and possibly former vice president Walter Mondale, he is answering a call that only he has heard.

This is also true of Gary Hart, a thoughtful man who nevertheless just barely managed to win reelection in Colorado. It is somewhat less true for John Glenn, a genuine hero of the space program, but a politician whose constituency is more like a fan club.

This is true of Ernest Hollings, a respected senator, but one without a national following. This is true, even, for Alan Cranston, a landslide winner in California but, until he himself mentioned it, virtually unmentioned as a presidential candidate. And it is true in spades for Askew, whose chief selling point is his own estimable character.

This is certainly not the case with Ronald Reagan. Not only is he the president, but he is (maybe more important) a spokesman for a significant wing of the Republican Party. The other possible exception is Walter Mondale. By virtue of being the former vice president and of cultivating the constituencies that constitute the Democratic Party, the only way he could not be a candidate is by declaring his intention not to run.

For the others, such statements would be inappropriate. You can only say no if you are asked. Almost no one has asked. No one went to them and said, golly, they just had to run. Like dogs, they heard a whistle only they could detect and took off at a run, hoping to assemble temporary constituencies the way developers assemble parcels of land.

What we have here is a system that has been turned upside down. Primaries, caucuses, federal matching campaign funds and, especially, television, have inverted the political process so that now presidential candidates are imposed from the top down instead of from the bottom up. Announce, organize like the devil so you win a primary or a caucus and you are--mostly because you say so--a candidate. What is missing is a constituency--a large group or groups of people who care about the candidate and share his values. Instead, you get a mystery-man candidate--someone with an obscure record whose only striking belief is in himself.

Because many of these candidacies are largely self-propelled, we--you and me--must now try to figure out who these men are and what they would do if they should become president. By and large, it's true, things could be worse. Regardless of why they are in the race, the present crop of candidates is hardly a stew of incompetence, and Richard Nixon proves that familiarity (at least on his part) can breed contempt--if not of court, then certainly of the electorate. But except for Mondale, Reagan and to a lesser extent McGovern, the candidates are unknown quantities, and even Mondale became nationally prominent occupying a largely ceremonial office.

This more than the remoteness of the election may account for why the campaign seems to be taking place "out there"--a roadshow every bit as ethereal as Liz and Dick touring the country in "Private Lives." The problem is that the process has been reversed. The candidates want us to listen to them. That's nice. But they should have listened to us first.