For the record, "Yes we can" emerged as a slogan later and less deliberately than one might think. The year was 1972, three years after César Chávez had appeared on the cover of Time magazine and two years after he had led farmworkers to a major victory against grape producers in California. Chávez was in Arizona trying to reverse a law prohibiting strikes by farmworkers during harvest time. Supporters of Chávez told him the law couldn’t be repealed. "No se puede," they said. Dolores Huerta, a colleague of Chávez’s, disagreed. "Sí! Sí se puede," she insisted. After hearing Huerta’s words, Chávez anointed Sí se puede! as his new rallying cry. Or so the story goes. In any case, the skeptics turned out to be right: No, no se puede, at least in Arizona. The law remained in effect. Still, a potent motto had been coined.

While the origins of Sí se puede may be linked to failure, the slogan is arguably no less powerful for it. The verb phrase (in Spanish) is "can be done," not "will be done." Success isn’t guaranteed or even likely. It’s simply possible. And that’s compelling in itself. Given the force of the catchphrase, it’s odd that no major politician adopted it until Barack Obama came up with a "Yes we can" campaign in 2008. It’s also fitting that Obama wound up drawing heavily on the lessons and methods employed by Chávez four decades earlier.

César Chávez was born in Yuma, Arizona, in 1927. His father, a farm owner, was unable to hold on to his land during the Great Depression, and the family moved to California, finding work in the fields. It was miserable, naturally. César went on to other things, serving in the Navy in World War II, working as a community organizer in the 1950s, and founding the National Farm Workers Association in 1962. The NFWA would later merge with another agricultural group (the Agricultural Workers Organizing Committee) and become the United Farm Workers.

In 1965 Chávez started organizing California’s agricultural laborers in earnest. The United States had recently done away with a program in which foreign temporary workers, called braceros, would be shipped in from Mexico each year to pick crops during harvesttime. Having braceros out of the picture made organizing U.S. farmworkers much more feasible. But the challenge was still formidable. Most people toiling in the fields were uneducated, fearful, and reluctant to take any chances with what little pay they earned. Also, U.S. labor law exempted (and still exempts) farmers from work rules that prevailed in other industries under the Fair Labor Standards Act of 1938. Unlike, say, steelworkers, farmworkers couldn’t organize using ordinary union elections.

Instead of being daunted by the absence of numerous FLSA protections, though, Chávez and his coworkers saw opportunities. Their weapon was the boycott, and their target was table grapes--along with any entity that helped make table grapes available to the public. For union workers covered by the FLSA, "secondary boycotts" of this sort are illegal. A unionized steelworker, for instance, can go on strike against her employer, but she may not call for a boycott of Sears for carrying products made with steel from her plant. Farmworker unions, not protected by the FLSA, are exempt from that kind of restriction. Taking advantage of this, the UFW sent volunteers across the country to pressure every supermarket possible to stop offering nonunion grapes. The campaign took off, and, during the late 1960s, conscientious liberals all over the country steered clear of the forbidden fruit. Chávez, an admirer of Gandhi and a devout Catholic, consistently advocated (and practiced) nonviolence, earning himself national adulation and visits from public figures such as Bobby Kennedy. In 1970, the major grape growers gave in, and the UFW got a contract guaranteeing workers $1.80 an hour in pay (a fifteen-cent raise) and a health and welfare fund. It was a remarkable victory.

The UFW had a few more big achievements in the 1970s, including a 1975 law in California that gave farm laborers the same rights to organize that workers in other industries enjoyed. Surprisingly, though, by the early 1980s the organization had run out of gas. When Chávez died in 1993, the UFW and its leader were widely admired but no longer powerful. There were legitimate external reasons for this: The public had lost interest. Conservatism was in the ascendant. Illegal immigration had surged. But the rapidity of the UFW’s decline was due mainly to Chávez himself, who fell under the spell of kooky gurus and began to purge many of his most valuable employees, often accusing them of being Communists or traitors. With success had come disagreements over where to take the union next, and Chávez, for all his asceticism and modesty, couldn’t tolerate challenges to his authority.

In his book Beyond the Fields: Cesar Chavez, the UFW, and the Struggle for Justice in the 21st Century, San Francisco lawyer and activist Randy Shaw doesn’t dwell on the decline of the UFW. Instead, he focuses on numerous successful organizing efforts of the past decades and attempts to show how they can trace their roots back to Chávez and his union. The UFW may have lost a lot of talented people, but, as Shaw demonstrates, they went on to have a major impact on public life in other ways.

The alumni of the movement have indeed been impressive. Miguel Contreras, a farmworker who started as a UFW boycott organizer in the 1960s, eventually became the chairman of the Los Angeles County Federation of Labor and a political heavyweight who helped mobilize Latino voters and turn the region from red to blue. (Hilda Solis, Obama’s secretary of labor, owes much of her career to Contreras.) Jerry Cohen, a brilliant lawyer who devised many of the UFW’s cleverest legal tactics, went on to become a master of class action litigation against badly behaved corporations, like Union Carbide in 1984 and Exxon after the Valdez oil spill in 1989. Marshall Ganz, the UFW’s chief field organizer, became a grassroots guru for politicians, including Alan Cranston in 1986, Nancy Pelosi in 1987, Howard Dean in 2004, and Obama in 2008. These are just a few among of the dozens of UFW alumni who stayed involved in social activism.

The Obama campaign, which drew directly on much of Ganz’s methodology, represented UFW-style organizing at its best. Instead of hiring staff to go door to door or man telephones, the campaign hired people whom it trained to be organizers. These organizers would in turn recruit local leaders and volunteers and train them up. When one volunteer stumbled upon an enthusiastic convert, the convert would be enlisted as a new volunteer. There was outreach to religious leaders. There was an emphasis on youth. There was relentless idealism. César Chávez would have been delighted.

Shaw’s book is the product of extensive research, and it’s invaluable for anyone interested in the evolution of unionization over the past forty years. California takes center stage for much of the story, and Shaw shows how UFW alumni helped to shift the political power balance of the state decisively to the left. Shaw also includes charts and lists of former UFW staffers and where they’ve ended up. It’s a reminder that a well-organized and passionate movement can lay the groundwork for future success even when individual campaigns fail.

While Beyond the Fields manages to link UFW alumni to a wide variety of political developments over the past twenty years, however, it’s less persuasive in assessing cause and effect. After noting Chávez’s ineffectual campaign to overturn the antistrike law in Arizona, for example, Shaw observes that, nevertheless, the "UFW’s voter registration efforts led to the election of … the state’s first Mexican-American governor, in 1974." Is there evidence for this? There may be, but Shaw doesn’t offer any. In another passage, Shaw relates the story of how UFW alumni organized a 1980s boycott of coffee producers who purchased beans from El Salvador. "The three [major coffee-producing] corporations, who controlled 80 percent of [El Salvador’s] coffee imports to the United States, were now pressuring the Salvadoran government for a peace settlement," writes Shaw. "On January 16, 1992, a peace agreement was signed." A lot of the book is like this.

As for the debates that surrounded the UFW in the 1960s and ’70s--and whether business leaders, farm owners, and Republican politicians had any grounds for opposing the UFW’s efforts--Shaw has little to say on the subject. Republicans make brief appearances in the book as one-dimensional allies of big money. But the story was always more interesting than that. Farming is no fun for the fieldworkers, but it’s no picnic for the growers either. It’s a volatile, often lousy, way to make a living. And labor disputes in agriculture are a special business because of how Mother Nature gets involved. For a grower whose workers go on strike during harvesttime, when a field of fruit is only days away from rotting on the vine, the danger isn’t just a dip in your profits. It’s ruination. Your workers have you by the strawberries. Policymakers who seek to intervene in this sort of conflict often come up with bad ideas weighted toward one side or the other, but they aren’t necessarily just venal, either.

A footnote on the issue of immigration: these days both the seal-the-borders crowd and the open-the-borders crowd claim César Chávez for their side. Both seem to be stretching it. Shaw, who appears to lean toward the open-the-border side, contends that Chávez didn’t mind illegal immigration per se, merely illegal immigration when it took the form of strikebreaking. But the distinction is strained. The arrival of myriad illegal newcomers made holding the union line extremely difficult, and Chávez understood this. When growers trucked in Mexican laborers to get around strikes, Chávez demanded that the Immigration and Naturalization Service step in. This made him a bit of an immigration hard-liner, to the dismay of many of his colleagues. But Chávez was also too much of a softie to ever advocate kicking people out en masse. If he had a consistent opinion--and it’s not clear he did--it probably boiled down to this: Join the UFW, and you’re fine, whatever your nationality. Scabs, go home.

Today, sadly, the UFW has lost much of its luster. In 2006, a Los Angeles Times series painted a particularly bleak picture of an organization that had strayed from its founding purpose and principles. But Chavez the man remains justifiably revered. Despite his flaws, he was undoubtedly blessed, or cursed, with an unusual abundance of concern for his fellow creatures. (He was even a vegan, out of compassion for animals.) And his decency was contagious. Those who once worked with Chavez are varied in their pursuits today, and their politics range from centrist to super-left, but they tend to be alike in honorable motivations. Chávez never appealed to ethnic chauvinism. He never countenanced violence. He never cashed in. He was inclusive, peaceful, and faithful to his principles, leading from the front. "When you work and sacrifice more than anyone around you," he once said, "others feel the need to do at least a little bit more than they were doing before." That’s why people put up with years of hardship to work with him, and it’s why they achieved such improbable aims. Well, sí se puede.