Denver — Labor's big political gamble is paying off. Last October, the AFL-CIO made the unprecedented move of endorsing Walter Mondale for the Democratic presidential nomination - before a single primary or caucus had been held. In hindsight, the risky strategy worked. Union officials like Silver Salazar see labor more politically energized and united than ever.
''We used to get very few members to attend the union meetings. (Now) they're starting to attend,'' says Mr. Salazar, a member of the Steelworkers union and southern Colorado president of AFL-CIO's Labor Counsel for Latin American Advancement.
Local union officials are finding more activity and participation ''than they've seen in a long time,'' adds Alan Kistler, head of the federation's organization and field service.
On Sunday, representatives of the AFL-CIO's member unions formally endorsed the ticket of Mr. Mondale and Geraldine Ferraro. Though it was a foregone conclusion, the move by the labor officials gathered in Denver was reason for union celebration.
''We had some rough sledding along the way - some defeats and some close calls,'' AFL-CIO president Lane Kirkland told his enthusiastic audience. ''But Fritz Mondale proved that he could stand up under fire and be all the stronger for it. And so did we.''
After poor turnouts in New England, the AFL-CIO made changes in its get-out-the-vote strategies that garnered big support in states like Alabama, Illinois, and Pennsylvania that were key to Mondale's rebound. The former vice-president wound up winning 7 of the 10 states with the largest blocs of AFL-CIO-affiliated unionists. Overall, the federation estimates that roughly 40 percent of Mondale's support in the primaries and caucuses came from union households.
Unions' early involvement in the political process allowed them to learn from their mistakes, says Richard Hurd, a labor economist at the University of New Hampshire. In that state's primary, unions' reliance on phone banks turned off many workers, he says. Now, more attention is being focused on building a grass-roots network and involving union activists in the campaign.
Because of this, ''union members are more likely to vote for Mondale-Ferraro, '' he says. ''Whether or not that's enough (to beat President Reagan) is another question.''
For their part, union officials make clear that they did not win the nomination for Mondale. And with 13.8 million members in AFL-CIO-affiliated unions, a small number in terms of the overall electorate, they do not contend that labor alone can win a general election.
''Unions have never said they could deliver votes,'' says Mr. Kistler of the AFL-CIO.
''I don't think unions persuade people to vote,'' says Charles Craypo, the new chairman of the economics department at the University of Notre Dame. ''I think they make the difference where the momentum is already in that direction.''
But AFL-CIO unions do hope to have an influence greater than their numbers might indicate.
Officials say thay aim to boost Mondale's share of the labor vote over Jimmy Carter's totals four years ago. In 1980, President Reagan is estimated to have commanded 40 percent of the vote among union households (homes with at least one union member in the family). The federation hopes to hold him to 35 percent this time, while increasing the overall labor turnout. Officials want to increase voter registration among union households from 60 to 85 percent by November.
With roughly 1 million members, the American Federation of State, County, and Municipal Employees hopes to register 75 percent of its members, says Jack Howard, assistant to the president of AFSCME.
The AFL-CIO doesn't represent all unions. Jackie Presser, president of the Teamsters union, supports the President.
Still, much of the labor movement appears to blame Reagan policies for its recent setbacks. In fact, steelworkers may be more motivated against Reagan than for Mondale, says Salazar of the Steelworkers union. Still, enthusiasm for the ticket is apparent - not only for Mondale, but for Ms. Ferraro as well. ''We've talked about it,'' Salazar says. The feeling is ''she'd probably make a darn good president.''
Even if Mondale should lose the election, the unions are building a broad foundation of activists that could be very useful for future political action, Professor Hurd adds.
Top 10 AFL-CIO states And who each state's voters backed during the '84 Democratic primaries and caucuses :Members Mondale Hart New York 1,700,000 44.8 27.3 2. California 1,200,000 37.4 41.2 3. Pennsylvania 1,100,000 46.9 34.9 4. Illinois 1,000,000 40.535.3 5. Michigan 857,000 50.4 32.2 6. Ohio 760,000 40.3 42.0 7. New Jersey 535,000 45.1 29.5 8. Texas 400,000 50.0 27.1 9. Massachusetts 400,000 25.8 39.1 10. Maryland 335,000 43.5 24.9