What voters didn't learn from the debates, and how to do better next time

Two debates down; one to go. But the American voter has probably been more titillated than informed by the process so far. It's too late for the League of Women Voters to sell a drastic change of format to the candidates' handlers for the last debate this year. But League President Dorothy Ridings might leave a note in the 1988 calendar reminding her successor to hold out for a different approach when she starts dealing with that year's nominees.

Despite the statistics bandied about by the debaters, viewers learned little except generalities and exaggerations from both sides about:

(1) How to revive uncompetitive American industries without wrecking the world economy through protectionism.

(2) What specifically can be done about the deficit, interest rates, and lagging exports.

(3) How to rescue the ballooning medicare budget.

(4) Which is the most fair, simplest approach to tax reform.

(5) What specific aims Washington should have in negotiating with the Soviets.

(6) Whether military and civil-service pensions should be reviewed as part of defense budget cutting.

(7) Which weapons-development programs can be stretched out over time to save money.

Despite the frequency with which social security was batted back and forth during the first Reagan-Mondale debate, there was no serious discussion of two hard issues:

(1) Whether there is any reason to pay retirees - particularly those who don't need the money - far more than they have contributed to social security.

(2) What is to be done to prepare for the future, when the retirement pay of the ''baby boom'' generation will rest upon the salary withholding of the ''baby dearth'' generation that followed.

It will be interesting to see whether the Oct. 21 foreign-policy debate fares better on specifics. Voters already know Mr. Mondale is committed to annual summits with Soviet leaders, moving the US embassy in Israel from Tel Aviv to Jerusalem, and trade protection for autos and steel.

Mr. Reagan is committed to further exploration with Moscow. But will other important topics be discussed in detail? For instance, what does Mr. Mondale mean by ''quarantining'' Nicaragua? When and under what conditions would Mr. Reagan meet with Soviet leader Chernenko? How would Mr. Mondale see Brazil and Mexico paying off their debts if their steel and other exports are prevented from competing in the big American market? How much would each candidate be willing to budget for ''star wars'' missile defense research?

Any political realist looking at this list of issues is likely to snort. Traditional wisdom has it that you can't snooker a shrewd candidate into talking in anything but vague generalities, for fear of alienating one interest group or another.

But the league shouldn't give up. Against all traditional wisdom, Mr. Mondale and Mr. Reagan spoke both thoughtfully and precisely in their first debate about that most sensitive question, abortion. Why not try to create a situation where there can be more of such thoughtful answering?

First, with due respect to school debate coaches, it would help to get rid of the trappings of that rigid format. Let the candidates sit down. There are enough privations involved in running for high office without having to stand for 90 minutes as if one is in a police lineup.

Second, experiment again with having just a single, neutral, but persistent questioner. Perhaps one for domestic policy; another for foreign.

Third, give each candidate the same overall time limit, but allow some flexibility in the time given to discussing individual subjects. If Candidate A has an detailed plan for dealing with deficits but little to say on ''star wars'' defense, he or she might answer accordingly. The American voter can get a clearer picture of the candidate's priorities that way.

Objections abound. Considering the difficulty the league had in finding four agreed-upon reporters for the Louisville debate, the choosing of a single, balanced interrogator would obviously be difficult. But it should not be impossible. The McNeil-Lehrer show's method of questioning two opponents alternately about an issue provides a good example of fair inquirers at work.

The usual objection to this more thoughtful approach is that it isn't sufficiently gladiatorial to attract a large TV audience. The theory is that viewers weaned on ''Dallas'' and Monday night football will find only a simulated presidential boxing match exciting enough to stay tuned.

But a more educational encounter between the contenders who spend our taxes and tend the hotline to Moscow need not be dull. It would, after all, still be the only direct confrontation between the two rivals (give or take a few Al Smith dinners and B'nai B'rith lunches). It comes at the climax of the campaign. And having the two sitting down with a savvy questioner - rather than standing rigidly with three questioners and a time clock - should not diminish the inherent drama. It might enhance it.

None of this examination is meant as criticism of the league. Its officers have spent scores of hours in recent years trying to get rival campaign advisers to agree on format. The safest common denominator has usually won. But, fortunately, every four years there is a new ball game. And if league officials start to work on the two managers early enough, the next presidential encounter could serve voters better.