Labor Day 1984 finds organized labor fighting an unprecedentedly intense battle to unseat a president and trying to recover from its battering by technological change, foreign competition, regulatory decisions and recessions in key industries.

These challenges confront labor leaders such as AFL-CIO President Lane Kirkland, who steered his 13.7 million-member federation to its first pre-primary presidential endorsement -- of Democrat Walter F. Mondale -- and is leading labor's most costly and extensive electoral campaign.

"We do not contend that political action alone can solve all of our problems," Kirkland said in his prepared Labor Day message, " . . . But however hard we work, we cannot succeed in a hostile political environment."

For organized labor, most of the news in 1984 has been bad: the rise of "concessionary" bargaining in which unions' past gains have been eroded sharply; decisions by the courts and the National Labor Relations Board that have hindered labor's ability to organize workers; the continuing advance of automation, and competition from cheap labor abroad and nonunion labor at home.

Yet, the steep drop in union membership appears to have bottomed out. There has been progress in organizing unions in state and local governments and among "service" industries, such as hospitals and nursing homes. Female and minority participation in unions also has increased.

On the political front, never before have so many unions spent so much time, money and energy on a single battle, the attempt to defeat President Reagan, a fight they fear they may lose.

Estimates of union funds and staff time expended in political efforts run to more than $20 million -- the bulk of it on the presidential campaign -- plus $20 million in projected 1983-84 political contributions by individual unionists.

In pushing for the early endorsement of Mondale, Kirkland placed the AFL-CIO's clout and his own on the line. When Mondale faltered in the early primaries, "we went through our darkest hours," said Murray Seeger, AFL-CIO director of information.

"We were tested, but we came out of it in good shape," he said, because many considered union support to be the deciding factor in swinging several late primaries to Mondale.

Labor leaders contend that the Reagan administration has a decidedly antiunion tone, citing the firing of more than 11,000 striking air traffic controllers in 1981 and the appointment of corporate-oriented conservatives to the NLRB, the Labor Department, the Occupational Safety and Health Administration and other agencies dealing with the work place.

Reagan's actions have unified labor leadership, labor officials said. (The 1.9 million-member International Brotherhood of Teamsters is the only major labor union that has endorsed Reagan.)

"I have been in the labor movement 27 years, and I have never seen this kind of activity, concerted activity," said Gerald W. McEntee, president of the 1 million-member American Federation of State, County and Municipal Employes. "And you can give much of the credit for that to Ronald Reagan."

But it remains to be seen whether labor's perceived unity will translate into votes: about 22 million Americans, 20 percent of workers, belong to unions, and the AFL-CIO traditionally assumes that Democratic candidates will get 65 percent of their votes and Republicans 35 percent. But in 1980, it is estimated that Reagan captured 40 percent to 45 percent.

Voter registration is a major part of labor's political effort, Seeger said, with the push aimed at "the 30 million-member AFL-CIO family" of workers, spouses and their voting-age children. The federation estimates that 55 to 60 percent of that "family" is registered and is seeking to increase it to 80 percent.

Kirkland today said, "The meaning of Labor Day has been dishonored by a president who professes warm regard for working people on that one day and exhibits icy disdain for them on the other 364."

Yet the economic recovery may draw voters to Reagan. The unemployment rate, which peaked at 10.8 percent in December 1982, is 7.5 percent.

The slowing of inflation has also benefited workers, as figures from the Bureau of Labor Statistics indicate: "real compensation" -- wages adjusted for inflation -- plummeted during the recession in 1981 to 95 percent, meaning that workers had taken a 5 percent cut in buying power since the 1977 base year. But real compensation climbed back to 99.8 percent early this year.

From labor's viewpoint, the wage gains of the past year have been paltry, especially when measured against resurgent corporate profits. "Workers are not participating in the recovery . . . , not sharing the wealth," said Rudy Oswald, AFL-CIO research director.

Commerce Department figures show after-tax profits rising 34 percent for the first half of 1984 compared with the same period in 1983, while wages and benefits rose about 5 percent during that period, according to the AFL-CIO.

Unions are winning almost half of the NLRB-supervised elections to determine whether workers want unions, a rate that has remained stable since 1974, according to Charles McDonald, the federation's assistant director of organizing. But the number of elections sought by workers plummeted during the recession: from 8,900 elections covering 204,000 employes in 1977 to 3,400 covering 80,000 last year.

"People feel lucky to have a job and don't want to rock the boat, and unions definitely rock the boat," McDonald said.

Unions have been in retreat on several fronts: nonunion wage settlements exceeded those for unions for the first time last year; employers, despite the economic recovery, are still forcing "givebacks," such as reduced health benefits and "two-tier" wage systems that reduce the pay of new hires; and the NLRB has reversed pro-union rulings and has made it easier for employers to shift work to nonunion plants, fire workers for certain union activities and fend off organizers.

Labor is fighting back, in some cases with new weapons. The AFL-CIO and major unions, such as the United Auto Workers, are launching million-dollar television advertising and programming efforts. Labor also has been successful in several "corporate campaigns" in which such union-resistant employers as the J.P. Stevens Co., Litton Industries and Beverly Enterprises have been pressured into settlements by protests aimed at the companies' stockholders, board members and bankers.

Retreats by labor also, in some instances, have been linked to advances, such as the Eastern Airlines settlement last winter. In that pact, three unions accepted pay cuts of about 20 percent but ended up owning 25 percent of the beleaguered airline's stock and placing four members on the board of directors.

What will happen to organized labor if its presidential candidate loses?

"If we lose," Seeger said, "then we knuckle down, reorganize and get ready for the next fight. Kirkland has said the great beauty of our political system is that you always get another chance next time."