FOR THOSE WHO cared about the candidacy, the 1976 experience must have been discouraging. How else could you describe a first-place finish (by 10 percentage points) in the Iowa Democratic precinct caucuses that did not lead to a single invitation to appear on the Today show, the Tonight show or the Tomorrow show? All the attention, after that election four years ago, went to the Iowa second-place finisher, former Georgia governor Jimmy Carter. And shortly afterward, this 1976 candidacy ended with a quiet and dignified withdrawal.

The year 1980 would see no repetition of errors made in 1976. This time there would be no peaking too early. The two Democratic front-runners and the one Democratic also-ran would set the early pace. The candidacy would not even surface until the critical late primaries, and then only to show that the candidate could still draw support at the polls, where it counts.

Texas was the first big splash. Running principally in the Democratic primary, Uncommitted received more votes than George Bush received in the Republican primary. In fact, if the votes Uncommitted drew that same day from Texas Republicans are added to his Democratic total, he also defeated Ronald Reagan. Mr. Bush got 256,616 votes; Mr. Reagan, 263,616 votes; Uncommitted, 264,163 votes. Texas was no lone star in the Uncommitted firmament. Just last Tuesday he captured 18 percent of the Democratic presidential primary vote in Arkansas, while in Nevada he beat Sen. Kennedy and fell only 2,666 votes behind President Carter.

As for California, which holds its primary next Tuesday, the Field poll shows that both Jimmy Carter and Edward Kennedy have lost ground over the past month. Mr. Carter slipped from 39 percent of the Democratic vote to 33 percent; Mr. Kennedy, from 48 percent to 33 percent. The only candidacy showing any forward movement in the Field poll during the same period was that of Uncommitted, whose support grew from a marginal 10 percent to a challenging 27 percent.

The surprise is that the historic pattern is not holding in this Democratic election. If pushed, fervent partisans of Uncommitted will admit as much. Almost invariably in the past, Uncommitted has run far stronger at the outset of any campaign that at the end. As voters have gotten to know the other candidates better, their support usually has grown and Uncommitted's has faded. But this year, as indicated by the Texas and Nevada results and the California surveys, Uncommitted is coming on strong.