Thousands of journalists, at a cost of tens of millions of dollars, labored to convey information and meaning about the Republicans in Detroit and Democrats in New York. Despite all that effort -- or dare we say because of it -- soundings across the nation show that relatively few people were paying much attention.

That result could well prove a clue to this election. Even more this year, the turnout on election day Nov. 4 will be critical. After watching the two parties at their conventions, there's no doubt which one emerges with more unity, spirit, and hunger for victory.

The Republicans, small though they are in terms of their share of the registered voters nationally, begin this campaign with a clear intrernal psychological edge. If the public reaction of general disinterest of the two conventions is any guide to voter behavior in November, this year will see a further decline in citizen participation at the polls. That will work for the revitalized Republicans. The television ratings at the two conventions carried a political message. In the largest population market of New York, the opening sessions at both gatherings saw the GOP attracting more people. That occurred despite the greater drama and sense of contest among the Democrats, with their fight over an "open" convention and the clash between the Carter-Kennedy wings -- and in a metropolitan area that is the nation's greatest Democratic stronghold.

The Republicans were getting through to their faithful, the Democrats weren't.

After the Republicans finished their conclave, they published an assessment by Bill Brock, the party chairman. "Our party's national convention in Detroit last month was one of the most joyful, united, and successful events in all our adult lives," he said.

He was uttering partisan propaganda, of course, but accurately reflecting the tone of the GOP.

The Democrats, or so it seemed to this observer, were signgularly dispirited throughout. There was an underlying tension throughout their convention, and it never was broken by the end.

Obviously, the major reason was the struggle between President Carter and Sen. Edward M. Kennedy. Their differences went beyond political approaches to issues; they were intensely personal, born out of mutual suspicions and misunderstanding, upbringing and outlook. A year ago, in the critical days when Kennedy was being pressed to run, Carter never could bring himself to put his arm around his rival and ask for his help. When he finally did, after the long and bitter nine months' fight following his public boast to "whip his ass," it was too late. "Ted, your party needs -- and I need -- your idealism and dedication working for us," the president said from the podium at Madison Square Garden.

Kennedy already had given his pledge to work for the party and for the president. But you didn't have to be a psychiatrist to sense their still profound uneasiness with one another when Kennedy finally joined Carter on the platform in the traditional unity sense that always ends political conventions.

The tabloid New York Post, a paper given to sensationalism and displays of bosomy pin-up endeavors, this time perfectly captured the Carter-Kennedy relationship in its Friday afternoon bold headline: BEST OF ENEMIES

But the problems besetting the Democrats went beyond the two men. On the convention floor throughout the week in New York, you could find delegates wondering about their present roles and worrying about their future ones at following conventions.

The reforms that had led to the big fight on the rules troubled even many of those who favored the Carter side. They were questioning whether future delegates should be bound so tightly before the convention began; it negated their own actions and independence, and they felt the end result was not in the best interests of their party.

Another source of disquiet was the belief, either vocally or implicitly expressed, that Carter stands in real danger of defeat in little more than 11 weeks with disastrous consequences for other Democratic candidates.

This was true among many Carter delegations as well as those favoring Kennedy, and it accounted for the extraordinary responses that came from the floor all week.

An ominous event occurred Wednesday night during the pro forma nominating speeches. Normally these times are the most boring at any convention, with speakers droning on and delegates listlessly turning to other matters. Not that night. Esther Peterson, the president's consumer affairs adviser, was making a traditional speech. She started invoking the names of Democratic presidents with whom she had worked, expecting, in the old way, to stir the party to applause. John Fitzgerald Kennedy's name drew loud applause. So did the sounding of Lyndon Baines Johnson's name. Then she mentioned Jimmy Carter's name. The hall erupted in boos -- angry, emotional, ugly sounding.

Some hours later Speaker Tip O'Neill read Kennedy's statement endorsing the platform -- and pledging to support and work for Carter. The reaction from Carter delegates was more a collective sigh of relief than exuberance; they clearly had been feeling down, and were defensive about their man's chances.

The most lasting impression of these two conventions contains a political irony. It lies in the significant differences between the two parties.

By virtually every standard, the Republicans represent the real minority while the Democrats reflect the widest range of American life and thought. Yet in a negative year of discontent it is the small group of true believers who begin with an advantage over their larger less harmonious competitors.