Why does Walker face a recall election?
He triggered an ideological civil war over the power of labor unions. When the Republican took office, in 2011, he faced a two-year budget deficit of $3.6 billion. To help close the gap, Walker pushed the "Scott Walker Budget Repair Law" through the state legislature, despite fierce resistance from Democrats. The law drastically curtailed collective-bargaining rights for all state government employees except firefighters and police, forbade the collection of union dues by payroll deduction, and required public employees to devote from 7 to 13 percent of their salaries to help fund their health insurance and pensions. Conservatives hailed Walker's efforts to curtail the salaries and benefits of public-worker unions, but unions throughout the nation were livid. In Wisconsin, pro-labor volunteers organized to recall Walker, gathering 900,939 petition signatures — about 360,000 more than needed. As the June 5 recall vote approaches, passions are white-hot. "I've never seen a division in our state like this," said Jon Dzurak, an assistant school principal in Milwaukee. "I'm not talking to some of my friends because of it."

Does the election matter outside Wisconsin?
There's no doubt about that. The recall, which pits Walker against Democratic primary winner Tom Barrett, is widely seen as a precursor to the 2012 presidential race, and as a proxy for the national battle between small-government conservatives and populist progressives. Walker is not alone in arguing that taxpayers can no longer afford to pay for the lavish benefits, pensions, and salaries of unionized government workers; Republican Govs. Chris Christie of New Jersey and John Kasich of Ohio are among the many who have vigorously taken up the chorus. Mitt Romney calls Walker "a hero." The Wisconsin governor has amassed a recall war chest of $25 million, at least 60 percent of it from out-of-state Republican donors, including casino mogul Sheldon Adelson and Amway founder Rich DeVos. "We've spent a lot of money in Wisconsin," said conservative donor David Koch of Koch Industries. "If the unions win the recall, there will be no stopping union power."

Are the unions mobilized?
They see it as a crucial battle, though they are disappointed in the selection of Barrett in last week's Democratic primary. In his eight years as Milwaukee's mayor, Barrett has frequently clashed with the city's public-employee unions. National and state labor organizations plowed at least $4 million into the campaign of Barrett's primary opponent, Kathleen Falk, who put union demands at the center of her campaign, but Barrett's statewide visibility and broader campaign message prevailed. The unions are now preaching unity. "All of the progressive elements, farmers that were in the fight, teachers that were in the fight, steelworkers that were in the fight, everyone has unified behind Mr. Barrett," said United Steelworkers President Leo Gerard. No wonder: Labor fears that a Walker win would inspire a nationwide wave of laws rolling back bargaining rights and benefits.

Are labor rights still the main issue?
They've become just part of a larger partisan argument over how best to deal with budget deficits, jobs, and the economy. "The irony is that collective bargaining, which was the instigation in all this, is fading into the background," says Marquette University pollster Charles Franklin. The Obama campaign, sidestepping the union issue, last week accused Walker of "putting the very wealthy ahead of what's best for the middle class." And Barrett, who lost to Walker by almost 6 percentage points in the 2010 gubernatorial election, prefers talking about jobs. Walker promised that his small-government approach would lead to the creation of 250,000 jobs in Wisconsin in his four-year term as governor; two years into it, only 5,900 new private-sector jobs have materialized. But Walker says his pushback against the unions has already saved Wisconsin taxpayers more than $1 billion. Last week, the state Department of Revenue announced new projections that Wisconsin will have a small surplus by the end of 2013.

Who will win?
In recent polls, Walker has moved into a lead ranging from 5 to 9 points. Walker's support among Republicans is strong: 86 percent of GOP supporters back him, while only 63 percent of Wisconsin Democrats view Barrett favorably. Walker's opponents say now that they've settled on their candidate, it's a new game. The electorate is already highly polarized: Only 4 percent of voters say they haven't made up their minds. Both Democrats and Republicans, said University of Wisconsin-Milwaukee political scientist Mordecai Lee, have embraced "Karl Rove's 2004 strategy cubed: finding your niche demographic and getting them to vote." The result is that on June 6, about half the state's voters will be triumphantly happy, while a slightly smaller percentage will be bitterly despondent.

'The laboratory of democracy'
Wisconsin is not often thought of as an influential state, but it has long served as a crucible for political movements that spread elsewhere. President Theodore Roosevelt called Wisconsin "the laboratory of democracy" for its innovative laws, many of them advocated by a fellow progressive Republican, Robert "Fighting Bob" La Folette, the state's governor and longtime senator in the early 20th century. The unlikely union of rural Republicans and Milwaukee social reformers that he formed passed the country's first progressive income tax, in 1911; a generation later, in 1959, Wisconsin became the first state to grant collective-bargaining rights to state employees. But that progressive tradition has long fueled a powerful resistance. Wisconsin conservatives keen to roll back union power passed a law in 1939 that limited the rights to organize and strike, a harbinger of the federal Taft-Hartley Act of 1947. In the 1950s, Wisconsin Sen. Joseph McCarthy led the conservative charge against communist conspiracies; in that very same era, Milwaukee had a string of socialist mayors. The current recall vote, said labor historian Rosemary Feurer of Northern Illinois University, "is part of a longer history and a longer struggle over ideas and social policy. History doesn't repeat itself, but it sure does rhyme."