In February of 2011, demonstrators occupied the rotunda of the capitol building in Madison, Wisc., to protest Governor Scott Walker’s attempt to push through a bill to restrict collective bargaining for most government workers. Scott Olson/Getty Images/file

If the states are the laboratories of democracy, Wisconsin has been smashing all the test tubes. Long known for its progressive political tradition, it has moved rightward, in ways once unthinkable. In 2010, Wisconsinites elected an anti-union Republican, Scott Walker, as governor; on the evening of Nov. 8, 2016, they pushed Donald Trump across the threshold to the presidency. Wisconsin had not smiled on a Republican presidential candidate in 32 years.

Most readers will recall the distressed masses that swarmed the state capitol in the winter of 2011. That year, Wisconsin’s lawmakers approved Act 10, Walker’s bill aimed at overcoming a budget deficit. Not incidentally, it also obliged many public employees to shoulder more of their pension and health-care costs, and sharply limited their collective bargaining rights.

In his absorbing “The Fall of Wisconsin: The Conservative Conquest of a Progressive Bastion and the Future of American Politics,” Dan Kaufman tells the story of just what happened. He also presents the state as emblematic of nationwide trends. Perhaps more than any state, Wisconsin captures the present turmoil on the left, and within the Democratic Party, as American liberalism seeks a way forward.

Kaufman begins with Norwegian immigrants, who fled economic hardship in the 1830s and ’40s in search of suitable farmland. Their strong egalitarian values and concern for the common good soon found expression in Wisconsin’s politics. The state played a leading role in the abolition movement and the founding of the Republican Party. After the Civil War, agricultural cooperatives and trade unions thrived. Wisconsin produced “Fighting Bob” La Follette, the Progressive candidate for president, who declared the purpose of government was “to alleviate economic suffering.” Wisconsin adopted the nation’s first laws providing for unemployment insurance and workers’ compensation.

But the gradual loosening of campaign finance laws starting in the 1970s, Kaufman argues, changed Wisconsin. Conservative organizations and contributors such as the Koch brothers targeted state legislatures across the country, with now familiar results. Walker’s divide-and-conquer strategy set unions against each other (police and firefighters were exempted from Act 10). More broadly, the deepening recession set struggling Wisconsinites against anyone perceived to have it better.

Amy Goldstein sensitively fleshes out the Wisconsin story in “Janesville, An American Story.” Until 2008, this midsized, middle-class city was home to a sizable GM plant. The company had begun manufacturing vehicles there in 1923, and along with being a major employer was integral to the community’s identity.

Goldstein’s ground-level reports on how the plant’s closure affected individuals (including native son and exiting House speaker Paul Ryan) form an anguished mosaic. The ripple effects ran from a suddenly superfluous day-care provider to the secret charity-supply closet at the high school. Laid-off workers thronged job-training programs but found limited opportunities when they emerged. Some became “Gypsies,” leaving their families for days at a time to work at distant GM plants. Surveys suggest that, amid falling real wages, most have permanently lowered their sights.

“If the people of Janesville are still sorting through the wreckage for a cause, author and political analyst Thomas Frank might tell them where to look: They have been sold out —by the Democrats. His “Listen, Liberal: Or, What Ever Happened to the Party of the People?” is a howl of betrayal. The party that should have had Americans’ backs, he argues, has deserted working people, chiefly by failing to address economic inequality.

Frank begins his critique with Jimmy Carter; lays waste to Bill Clinton; and painfully concludes that Barack Obama could have done much more to address growing inequality — he just preferred not to. In Frank’s view, the party of the people now serves a corrupt but self-righteous professional class.

Helena Rosenblatt offers a measured supplement in “The Lost History of Liberalism: From Ancient Rome to the Twenty-First Century.” A scholar at the City University of New York, Rosenblatt has meticulously researched the word’s history, unearthing forgotten meanings. She moves from liberalism’s roots in 19th century France and Germany to its growing association with the United States in the 20th century.

Gradually, an idea that began as moralistic — and warned against the dangers of selfishness — underwent a transformation. After World War II, conservatives associated liberalism with the kind of grand social schemes they believed led to totalitarianism. Liberals retreated to a position that emphasized individual rights but not necessarily generosity toward others. Rosenblatt invites a return to this broader, Wisconsin-style view.

At a moment when so many Americans are inclined or encouraged to turn against each other, it could be a stretch. During the 2011 protests, Wisconsinites were overheard wondering how so many teachers could find time to demonstrate. By then, Kathy Cramer, a political scientist at the University of Wisconsin, had been researching the state’s mood for four years. She wound up with a book titled “The Politics of Resentment.” She told Kaufman: “I was always proud to be from this place where people were so nice to one another.” In the end, she bleakly wondered: Are we?

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