POLL-TAKER PETER HART was right in his op-ed piece Friday taking issue with the criterion the League of Women Voters has established for participation in its presidential debates. Mr. Hart argued that the League's insistence that to qualify a candidate must have got 15 percent of the vote in various polls by certain fixed times wildly flatters the accuracy, the consistency and the significance of the poll-takers' product. "The use of survey research to determine who should participate in the 1980 presidential debates," he said, "is a perfect example of misuse of the tool of survey research. . . . There is no reason to believe that the next 80 days will find public opinion any more stable than it has been in the first 230 days of this year."

It is also a perfect example of something else: the disinclination of practically everyone these days to make judgments and to take the heat for making them. Instead, we have the universal search, it seems, for the perfect automatic "system," the social science dodge. What it says, or seems to say, anyway, is this: Look, you may have a complaint or feel that the result was too generous to your opponent or too ungenerous to you, but we can't help it -- that was the system and it was as objective as we knew how to make it. There is a general wash of science or science-ish-ness over all of this, a greatly misleading one; and that is why it was so useful for Mr. Hart, no basic denigrator of the polls in their place to make his pitch. The National Council on Public Polls, which includes George Gallup and Louis Harris, issued a similar warning to the League yesterday.

Now, there are about a hundred and eighty ways of seeing this one -- we are aware of that. The argument really concerns whether Independent candidate John B. Anderson will get to take part in the League-staged debates, and a lot of people who want him in and a lot who want him out feel the episode is pretty high-stakes stuff in this election. Therefore, it can be reasoned, the League needs to take precautionary measures, to seek protection in its objective-sounding criterion. But this strikes us, in any event, as a no-win situation for the League. It will not be able to satisfy all the morally toney claims made for and against inclusion by people who have something other than morally toney purposes.

Politics, as that great German county chairman, the late Otto von Bismarck, once observed, is "not an exact science." We would take it further. Politics is not even an inexact science. And political judgments, while making use of such information as public-opinion polling can provide, should not be abandoned to computer printouts and percentage points and the rest. Does John Anderson qualify to participate in the debates? Why doesn't the League decide?