WITH its ranks weak and the number of strikes at a 50-year low, ''Big Labor'' has lost much of its brawn.
But organized labor is seizing on a strategy that gives it more muscle in fights with management over wages, benefits, and other workplace issues.
The strategy, known broadly as a ''corporate campaign,'' uses everything from boycotts and proxy fights to lawsuits in an effort to alienate corporations from their suppliers, customers, lenders, and shareholders.
With the stakes high for both sides, management is striking back with proposed legislation and lawsuits charging unions with racketeering and defamation.
In Chicago, candymaker Brach & Brock Confections Inc. last week said it plans to refile a defamation lawsuit against backers of a long-running corporate campaign arising from job cuts at a local factory. Brach, based in Chattanooga, Tenn., alleges that labor activists defamed the company in an effort to force a change in ownership.
The defendants, including the Midwest Center for Labor Research and the community-based Save Brach's Coalition, call the Brach filing a SLAPP suit (for ''strategic litigation against public participation''). Their legal defense is supported by the Teamsters Union, which represents Brach workers in Chicago.
Brach is just one of many corporations besieged nationwide. From a supermarket chain in North Carolina to a steel mill in Louisiana to a custodial service in California, unions are using corporate campaigns to seek recognition or better contract terms.
''We will use old-fashioned mass demonstrations, as well as sophisticated corporate campaigns, to make worker rights the civil rights issue of the 1990s,'' said John Sweeney, the AFL-CIO's militant new president, in his acceptance speech in October.
The strategy has embittered some quarters of management. ''These campaigns are very savage and vicious and they certainly are not in the spirit of the American collective bargaining process,'' says Tom Donohue, president of the American Trucking Associations (ATA) in Alexandria, Va.
Labor leaders have embraced the strategy as part of a last-ditch effort. Today, only about 10 percent of the private-sector labor force is unionized, a drop partly due to company union-busting efforts.
In a bid at recovery, unions are boosting grass-roots efforts to organize nonunion workplaces. Meanwhile, corporate campaigns are growing as strikes have lost much of their potency. Walkouts are at postwar lows, partly because unions fear management will hire replacement workers.
How effective the strategies will be is unclear. But both sides agree the number of corporate campaigns is steadily rising.
Though some campaigns involve strikes, slowdowns, and worker demonstrations, their innovation lies in what is occurring beyond the workplace, including:
r Lobbying against the company in legislatures and opposing company bids for government contracts.
r Filing complaints with a spectrum of government agencies at various levels, provoking bad publicity and litigation costs.
r Promoting boycotts, souring the company's public image with negative publicity, and rallying community, religious, environmental, and other groups.
''Employers should prepare for an onslaught of union-inspired corporate campaign tactics,'' says a recent memorandum by the National Association of Manufacturers (NAM) in Washington.
The management counterattack is in its early stages.
A coalition including the NAM, ATA, US Chamber of Commerce, and Associated Builders and Contractors has publicized the excesses of some corporate campaigns. It has called for restraints on injunctions by the National Labor Relations Board that aid the strategy. It also seeks prohibitions against such campaign tactics as picketing lenders, suppliers, customers, and company officers' homes. And it has asked that corporations be allowed to disregard proxy resolutions brought by unions involved in collective bargaining or an organizing effort.
Rep. Peter Hoekstra (R) of Michigan, chairman of the House Oversight and Investigations Subcommittee, plans to meet informally with management and labor groups this month to determine the suitability of legislating controls on corporate campaigns.
Unions say such controls would infringe basic liberties.
Since such legislation would probably fall before a Clinton veto, companies for now must defend themselves with the same weapons as their union attackers.
''The most important thing a company can do in a corporate campaign is to get out its side of the story to the public in a very aggressive manner,'' says Jeffrey McGuiness, president of the Labor Policy Association Inc. in Washington.
Companies are also using lawsuits to pin down labor gadflies.
Bayou Steel Corp. of La Place, La., and Food Lion Inc. of Salisbury, N.C., hope to quash corporate campaigns by suing unions for allegedly violating the federal Racketeer Influenced and Corrupt Organizations (RICO) Act.
Bayou Steel alleges that after a failed strike, the United Steelworkers of America defamed the steelmaker before investors, ran negative newspaper ads, and filed hundreds of groundless complaints with regulators.
Food Lion, a nonunionized supermarket chain, claims that United Food and Commercial Workers set up a bogus consumer group that circulated false, sensational reports claiming the grocer routinely sold spoiled infant formula and other rancid foods. National media picked up the stories.
If a suit prevails, it would force corporate campaigners to ''make sure they are on really solid ground with the charges they level,'' Mr. McGuiness says.
The backlash against it is bound to fail, contends Ray Rogers, president of Corporate Campaign Inc. in New York, who in 1976 launched what is said to be the first corporate campaign. ''The only way to stop corporate campaigns,'' he says, ''is to create a dictatorship that wipes out workers' right to free speech.''