For the American labor movement, which marks its turning points with such dramatic events as the Homestead Massacre and the Battle of the Overpass, the fight for Magruder's supermarkets seems an unlikely landmark.

But the recent unionization of the Rockville-based grocery chain is a symbol of a significant shift for organized labor -- from traditional tactics for organizing largely blue-collar workers to new strategies for organizing the nation's burgeoning service industries.

Last month, after nearly a decade of failure, Local 400 of the United Food and Commercial Workers union organized the workers at the company's eight area stores by turning its back on a half-century of labor law.

Specifically, the union gave up on the National Labor Relations Board.

The union had tried working through the NLRB process, filing charges with the board to protest Magruder's alleged attempts to prevent union organizing. Local 400 had charged that the supermarket chain violated the labor laws by harassing employes in various ways about possible union activity.

Magruder Inc.'s management and legal counsel declined to comment or be interviewed for this article.

Local 400 filed the charges in July 1981. A year later, the board ordered the union to accept a settlement offered by Magruder. Under that settlement, the chain would post a single sign in a single store, declaring its intention not to interfere with organizing activities. That was when Local 400 gave up on trying to achieve its goals through the board.

"Using the board today is really a waste of time, money and effort," said Local 400 President Tom McNutt. The experience at Magruder's and elsewhere convinced him that the NLRB process "just wasn't working." So in 1982, the union decided to turn to "pure raw economic pressure" to force Magruder to recognize the union, McNutt said.

Late in 1983, the union prepared to begin informational picket lines at various Magruder stores. The first step was to notify shopping centers where the stores were located that the union intended to picket to inform the public about what it claimed were substandard wages and benefits.

But the picketing never took place.

"Within a few weeks," McNutt said, Magruder's began discussions with the union. According to McNutt, the company said it wanted a "reasonable solution" and began serious negotiations to allow the union to try to organize the grocery chain's 900 employes.

Last month, after a year and a half during which a majority of the company's employes signed union authorization cards, Magruder's voluntarily recognized Local 400 as the bargaining agent for its employes. Negotiations for a contract are about to begin.

Magruder's employes earn between $4 and $5 an hour, with no job security, no seniority provisions, no pension -- virtually no fringe benefits, McNutt said. UFCW workers at Safeway and Giant -- the area's two biggest supermarket chains -- earn up to $9.35 an hour after three years with the company. Senior clerks make about $12 an hour in wages plus about $3 an hour in benefits, according to the union.

McNutt, who has been successful in organizing other large retailing operations in the Washington area outside the food industry, said a key to getting Magruder's to agree to negotiate was the threat of adverse publicity. Once it was clear that the union would take its case to the public, the company agreed to talk, he said.

Local 400 had used a similar tactic successfully in the fall of 1981, when the Food Town/Price Shopper chain from Baltimore tried to enter the Washington market with a nonunion store. The union set up informational picket lines outside the store for three months. The company finally agreed to recognize the union and now has 15 union stores in the Washington area.

The Magruder's campaign is a local example of a national phenomenon; the tactics used by Local 400 are being advocated nationally by its parent organization, the AFL-CIO, as part of a strategy to organize new industries, primarily service industries, to offset the nation's shrinking union membership.

In February, after more than two years of study, the AFL-CIO concluded in a report on the evolution of work that organized labor must change to survive the scientific, technical and economic revolutions taking place in the United States today.

In its report, "The Changing Situation of Workers and Their Unions," the AFL-CIO committee expressed particular concern over what it saw as the recent erosion of public support for federal labor laws.

According to the AFL-CIO report, after years in which employers either "resisted unionization by improving their employes' wages and working conditions" or "complied with their legal duty to bargain with that union," attitudes have changed radically.

"The norm is that unions now face employers who are bent on avoiding unionization at all costs and who are left largely free to do so by a law that has proven to be impotent and a Labor Board NLRB that is inert," the report said.

To meet this new challenge, the AFL-CIO committee recommended that the American labor movement revert to much the same tactics it used more than five decades ago in a highly successful drive to organize the nation's basic manufacturing industries -- tactics that pitted public opinion against economic strength without ever getting into the hearing rooms of government.

The tactics used in the Magruder organizing campaign are being cited by top AFL-CIO officials as a prototype for other unions to follow as they try to organize new members.

Those tactics are working for the UFCW. Nationally, the union's membership growth increased in 1983 and 1984 after declining steadily in the early 1980s. After reaching a low of 38,940 new members in 1982, the union grew by 58,841 members in 1983 and by 65,245 members last year.

By contrast, total union membership nationally has declined 14 percent since 1980 to 17.3 million.

McNutt attributes the membership gains "directly" to the tactical switch and predicts the strategy will continue to spread locally and nationally.

"We are going to see more of these tactics, particularly in the service industries. . . . The real growth area for unions is in the service sector," he said.

At the same time, McNutt said he would prefer to use the NLRB process if it worked -- that is, if it forced both sides to observe the labor laws. "When the board process works, it's effective."

Frustration with the process has been building for years, but has reached a crisis under the Reagan administration's board, which is very pro-employer, said Local 400's attorney, Carey Butsavage. The current NLRB procedure, with its lengthy delays and mild penalties, mostly against employers who choose to fight attempts to unionize, "lets companies violate the law without really having to pay the price," Butsavage said.

It is also costly. Local 400 spent about $300,000 on board actions in 1982 and 1983, "for nothing," Butsavage said. "I don't think the NLRB is worthless . . . but it's hard to justify the expense and time."

The union "would prefer to do it in a democratic way, to have an election, to let the employer tell his side, let the unions tell their side, and then let the employes decide," Butsavage said. "It's not pleasant to walk a picket line."

Of the many recommendations the federation made to its member unions, including the UFCW, three basic points appear to represent the heart of the new organizing strategy:

Creation of new categories of membership for workers not employed in an organized bargaining unit.

The committee said that nearly 28 percent of all nonunion employes are former union members, most of whom left their union because they left their union jobs. To keep these people on the union rolls, the federation has urged its members to create new categories of membership -- either on an individual union or a federation basis -- to permit a union member to keep his or her union membership and some benefits attached to that membership after leaving a job with a union employer.

The new union categories also could be used to offer some tangible reward to employes who voted with a union in a losing organizing effort. An AFL-CIO official said, for example, that if a union lost an election by a 500-to-300 vote it could create an "association" to provide some sort of benefits for the 300 who voted with it.

The use of "non-workplace pressure" to bypass the legal process when the legal system proves unresponsive.

This type of activity is generally referred to as a "corporate campaign." In a corporate campaign, the union, either by itself or with other unions, attempts to turn public opinion against the employer in an effort to achieve union recognition. These campaigns often take the form of consumer boycotts and other similar types of action aimed at the corporate profit margin.

Creation of a pilot project to explore the possible use of organizing committees financed by the AFL-CIO, in much the same way that the late United Mine Workers president John L. Lewis helped create the United Auto Workers Organizing Committee and the United Steel Workers Organizing Committee in the mid-1930s. The two committees eventually helped create today's auto and steel unions.

The most significant aspect of the committee report, according to several key labor officials within the federation, was the fact that it happened at all. "The most important part of the report is that the AFL-CIO for the first time focused on organizing the unorganized," said a union official familiar with the debate over the report. "Right now," he said, "80 percent of the people in the labor movement aren't doing any of those things."

For some union officials, the report is a clear signal that the AFL-CIO is prepared to try to revitalize a trade union movement that has been in decline for more than a decade. With the nation now essentially a service economy, employment in the basic manufacturing industries -- labor's basic strength since the 1940s -- has been sharply reduced. And the building and construction trades, another traditional source of union power, also have been decimated by nonunion employers.

The biggest growth within the labor movement in recent years has been among the service unions, such as the UFCW and the government employe unions. The UFCW, for example, is now the largest union in the AFL-CIO, with about 1.2 million members.

Throughout this decline, however, the focus of the AFL-CIO and many of its key unions appears to have been more on survival than expansion. One top union official suggests that until the federation issued its report last February, the dominant attitude among the labor leadership reflected a statement by the late AFL-CIO President George Meany more than a dozen years ago that organizing new members was simply not important.

In an interview with U.S. News & World Report early in 1972, Meany was asked why the total membership of the labor movement was not growing as fast as the country's labor force. His reply: "I don't know. I don't care."

Meany then went on to explain his lack of concern. "Why should we worry about organizing groups of people who do not appear to want to be organized?" he asked. "If they prefer to have others speak for them and make the decisions which affect their lives without active participation on their part, that is their right. . . . Frankly, I used to worry about membership, about the size of the membership. But quite a few years ago I just stopped worrying about it, because to me it just doesn't make any difference."

Meany's statements came when the AFL-CIO had tremendous political clout within both the Nixon administration and the Democrat- controlled Congress. Meany himself may have been at the zenith of his politcal power. It was during the first peacetime experiment with wage-price controls, and the AFL-CIO was an integral part of the government's anti-inflation machinery. Union leaders within the federation did their business with the federal government through George Meany.

And while unions weren't growing, one of the big issues among the manufacturing unions was not survival, but how to humanize the workplace and increase leisure time.

With its new report, the AFL-CIO and its top union leaders appear to be signalling a major attitude change toward organizing. The report seems to officially end the Meany era in the American labor movement.