AFL-CIO President John Sweeney has the muscle and votes to hand Al Gore just what he wants and needs: the money, manpower and prestige of an early endorsement by the labor federation.

And Sweeney wants to give this highly valued prize to the vice president, a politician he views as a loyal ally of organized labor.

But two things are holding Sweeney and other labor leaders back. First, they are reluctant to force an endorsement down the throats of federation members bitterly angry over the administration's free trade policies. Second, they want to be sure that an endorsement is not interpreted as labor's attempt to throw a lifeline to a drowning candidate.

"I want to endorse the strongest possible candidate and have the strongest possible support for the endorsement," Sweeney said in an interview. "I don't want to endorse a candidate who is not getting a good reception from the rank and file members."

Gore's strength lies with public sector government unions, most of which appear ready to back him. Most, but not all, opposition to Gore is concentrated in industrial and manufacturing unions that have experienced sharp membership declines as production has moved abroad and domestic products have faced rigorous foreign competition.

The opposition is based on Gore's support of free trade policies. But Gore's critics do not have a ready Democratic alternative since former senator Bill Bradley is also a strong backer of free trade, including labor's bete noire, the NAFTA treaty.

The endorsement of labor can be a crucial factor in Democratic primaries--Walter F. Mondale would not have won his party's nomination in 1984 without it--and recent developments have made it all the more salient.

For Gore, the endorsement, which requires the support of two-thirds of the delegates from 68 member unions expected to attend the AFL-CIO convention in Los Angeles next month, represents a needed boost for a campaign that has struggled to gain momentum. Most labor leaders believe the federation will endorse Gore next month, but it is not a sure thing.

Bradley has gained in some recent national polls and is running almost even with Gore in New Hampshire, which holds the first primary in the nation, and in New York.

The labor endorsement has become all the more significant because of the growing likelihood that Patrick J. Buchanan, an outspoken critic of free trade and immigration policies, will run for the Reform Party nomination.

While most current polls suggest Buchanan would be more damaging to the GOP than to the Democratic presidential candidate, labor leaders warn that Buchanan's message resonates powerfully with many industrial workers in the Midwest, the most likely battleground in a close election.

"It's like a George Wallace thing," said Gerald W. McEntee, AFSCME president and coordinator of political operations for the AFL-CIO. "Buchanan really struck some chords with blue-collar workers," he said, arguing that organized labor has to begin to make the case for Gore to its members as soon as possible.

McEntee, unlike Sweeney, has no reluctance in moving ahead with a Gore endorsement next month. Past tradition in labor has been to seek a consensus, but, he said, "things have changed [and] to get two-thirds of any group is not an easy project. Once you have the two-thirds, that is what the constitution states."

The unions most reluctant to endorse Gore include the Teamsters, the United Autoworkers, the Painters, and the Paper, Chemical and Energy Workers (PACE).

The Teamsters are worried that the administration-backed NAFTA treaty will open the Mexican border next year to low-wage truckers who will be allowed to compete for business that had been the province of U.S. truckers. The UAW has consistently opposed the administration over trade policy.

PACE officials are angry over what they view as anti-union privatization at government nuclear facilities in Tennessee, Kentucky and Ohio, along with Gore's disagreements with the forest products industry, which makes paper, over environmental issues.

"It's the industrial sector of the United States, period, that this administration has been totally unresponsive to," declared Kip Phillips, international vice president and director of government affairs for PACE. Richard Miller, a PACE policy analyst, was more outspoken, saying, "We've got huge problems with Gore because he has sanctioned union busting."

The International Brotherhood of Painters and Allied Trades is one of the few unions inclined to endorse Bradley. Bill Anderson, Painters vice president and political director, said Bradley got the support of 73 percent of local union representatives meeting at the Painters convention in Washington, and the Iowa local has already endorsed him.

"If the Democratic Party is going to win the White House in 2000, the candidate is going to have to articulate issues and stands that represent the men and women we represent. Senator Bradley is doing that," Anderson said.

Despite these complaints, the odds now favor a Gore endorsement, according to most of those involved in the debate. "To be honest, if the AFL blows the whistle, we will line up," said one of Gore's harshest critics in the labor movement.

The likelihood of a Gore endorsement increased sharply when George Becker, president of the United Steelworkers of America, indicated he would aggressively support such a motion. "I expect us to move in unison," he said.

The steelworkers and the administration have been at loggerheads over steel imports, but the recent adoption by the administration of a program to help protect domestic steel interests has taken the edge off the conflict.

"To be frank, there is nobody out there who has what we feel is the right spin on trade," Becker said. "But are we going to get out of the political process? Hell, no. We are going to be part of the political process."

CAPTION: Vice President Gore prays with Labor Secretary Alexis M. Herman and AFL-CIO President John Sweeney during Sept. 5 Mass in Detroit.