“Like my mom always said, ‘You see something that’s not right, it’s your turn to fix it,” said 45-year-old Chicago Wal-Mart employee Myron Byrd, who plans to be arrested in his first act of civil disobedience today. “And you can’t do it by yourself — you have to do it with others.” Byrd said he was driven to action by “high school”-level pay and workplace disrespect, and inspired by the courage of fellow workers and his mother’s civil rights legacy. “I’m sacrificing myself, along with others, to do this,” he told me, “to show Wal-Mart that hey, I’m not afraid, they not afraid, we not afraid.” In an e-mail to reporters, Wal-Mart spokesperson David Tovar said that “planned arrests” were “just another way to make these orchestrated events seem newsworthy,” and that “these aren’t real protests by real Walmart associates.”

Whether today’s action is bigger than last year’s “Black Friday” showdown remains to be seen, and likely depends on how you count: Would more protests, and more protesters, make up for a retaliation-fueled reduction in the number of Wal-Mart employees who go on strike to join them?

Wal-Mart’s first 50 years were free of Black Friday strikes – indeed, free of any coordinated walkouts in the United States. Then, 14 months ago, a wave of Wal-Mart supply chain strikes that started with crawfish-peeling guest workers and subcontracted warehouse workers spread to include the corporation’s retail employees, first in Southern California and then in cities across the country. Strikers were members of OUR Walmart, a fledgling non-union workers group that first announced itself in 2011; it draws funding, staffing and direction from the United Food & Commercial Workers union.

For the UFCW, Wal-Mart poses an existential threat, driving down standards for competitors and endangering hard-fought gains. “Our companies are saying, ‘If Wal-Mart can get away with it, why can’t we?’” an employee from a unionized Safeway told me as she prepared to join a Black Friday protest at a Maryland Wal-Mart last year. But the Wal-Mart challenge extends far beyond the company’s 1.3 million U.S. employees, or the UFCW’s 1.3 million members. By pioneering tactics to cut labor costs and avert labor organizing, and instigating imitation among suppliers, subcontractors, competitors and admirers across industries, Wal-Mart is hastening a transformation in U.S. work, toward an ever-more-present future in which workers – whether fast food cashiers or adjunct professors — lack living wages, workplace democracy, job security or even legal recognition as employees.

Faced with a future of declining leverage and relevance, U.S. unions have taken up a range of tactics on full display in the Wal-Mart effort, including “comprehensive campaigns” that wield political, legal and media weapons against a company’s brand, growth ambitions and consumer loyalty; “minority union” tactics in which smaller numbers of workers take bold public action to embarrass management and engage more reticent co-workers; organizing in solidarity across supply chains and national borders; short-term strikes designed to maximize public engagement and minimize the risk of retaliatory firings; and working with or through “alt-labor” groups that aim to transform workplaces without seeking collective bargaining.

Together, these tactics have forged the most serious challenge to Wal-Mart’s control over its U.S. workforce since the company was founded in 1962. It’s far outpaced the previous decade’s well-funded but anemic union-backed anti-Wal-Mart efforts, which involved bloggers and presidential candidates but comparatively little in the way of Wal-Mart employees. But the current campaign still faces nearly impossible obstacles, some of which have only become more visible in the year since 400-some strikers and thousands of supporters pulled off Black Friday 2012.

Chief among the challenges is this: While U.S. law generally bans companies from punishing workers for organizing (whether toward unionization or as part of a non-union effort like OUR Walmart), it does precious little to avert or avenge such retaliation when companies are dead set on maintaining control. In the months after 100-some strikers staged a several-day work stoppage and protest caravan to Wal-Mart’s June 2013 shareholder meeting, 23 of them were fired – exactly the scenario that’s kept many Wal-Mart workers on the sidelines. While “I do not think I have ever hated any one thing in my life” as much as Wal-Mart, one employee told me shortly before those firings began, he’d be keeping his mouth shut because “Wal-Mart does not tolerate dissenters.”