Once again, to the banks of the Charles, to the school that bears John F. Kennedy's name, they came -- the winners and the losers in the presidential campaign.

They came to the fourth quadrennial "campaign decision-makers' conference," sponsored by Harvard's Institute of Politics. For most of last weekend, they sat around a conference table and reexamined the strategies and tactics they had used in this year's battle for the White House.

As has been the case since these unique ventures were started in 1972, there was an extraordinary degree of civility and mutual respect among the 24 managers, pollsters and party officials who had so recently been antagonists. In the perfect democracy of the Kennedy School seminar room, the press secretary to one of the early victims of the Democratic primaries was on a par -- at least briefly -- with the White House assistant whose president carried 49 states.

As usual, the specific comments of the participants are off the record until the edited transcript of the proceedings is published in what should be a lively volume. But also as usual, the journalists in the room are free to write about their own impressions and about what we heard in the after-hours sessions, where the informal conversations again provided some of the most fascinating moments.

I was struck once more by the enormous gap between the resources the Republicans and Democrats bring to the presidential campaigns. It's not just money -- although the GOP's advantage in that commodity is significant enough. At least as important is the inequality in political research, polling and political planning. Time after time, Republicans were stunned to hear from the Democratic operatives that questions they assumed had been matters of major discussion and careful polling by their opponents had been decided in the dark, as it were.

Obviously, Walter Mondale's polling and planning were less comprehensive than Ronald Reagan's, because Reagan had a clear path to renomination from the start, while Mondale had to battle into July for his title as challenger. But in every one of the last four post-election conferences, including those in years when the Republicans were the out-party or had serious nomination fights, the same gap has been apparent.

There is something in the Democrats that makes them resistant to the systematic application of survey research and the discipline of developing detailed strategic plans for targeting and winning the necessary 270 electoral votes. Deep down, they are more inclined to rely on their instincts -- for better or worse.

No one -- literally, no one -- in this conference entertained or expressed the notion that Reagan's landslide victory was achieved by the superior genius of his managers. On the contrary, the Democrats readily conceded that the power of Reagan's personality and the relative prosperity of most American families were the fundamental building blocks of his triumph. The only serious debate was how much specific decisions -- such as Mondale's choice of Geraldine Ferraro and his endorsement of a tax hike -- added to or subtracted from the margin.

The more interesting argument, mostly offstage, concerned the implications of this election for the future. Many of the Republicans were sniffing the intoxicating aroma of a possible political realignment that would make them the majority party. The Democrats were mostly skeptical -- but scared.

Two points emerged more clearly here than ever before. There was remarkable agreement -- virtual unanimity -- among these 24 professionals, from the most liberal to the most conservative, that the GOP can maintain the advantage Reagan gained among the growing rnks of younger voters only if it puts its economic- opportunity message out front and subordinates its conservative social-issue agenda.

There was a lot of argument about the degree of impatience the proponents of the anti-abortion and school-prayer amendments will vent on the GOP if Reagan fails to deliver them in his second term. But there was no vocal challenge to the view that if Republicans emphasize those issues more than tax cuts and jobs, they will lose their handhold on the political future.

On the Democratic side, there was a gulf separating the views of those who think Mondale was trounced because of personal failings as a candidate and those who believe the liberal tradition he embodies has become pass,e.

A few -- mainly Mondale's managers -- think he will be viewed as an important transition figure from the party's historic past to a bright Democratic future. They see no reason to uproot the Democratic Party to reexamine its basic premises. But more of the Democrats, and almostall the Republicans, believe that fundamental reexamination must precede a Democratic comeback.