Walker appears in Mayer’s “Dark Money” as a “college dropout with no exceptional charisma or charm” who coasted to victory in Wisconsin’s 2010 gubernatorial election, after wealthy conservative backers identified him as a Tea Party politician with a simpatico ideology. As Kaufman details, Walker has given his donors a spectacular return on their investment, gutting collective bargaining rights for public-sector unions (exempting firefighters and police officers, who had supported his campaign) and slashing taxes by $8 billion.

Walker even paid lip service to his state’s past by calling one of his early pieces of legislation — the Wisconsin Budget Repair Bill, also know as Act 10 — “progressive.” But the tax cuts he enacted were so extreme that they inflated the state’s deficit to $2 billion. Kaufman describes 2011 and 2012 as a pivotal moment in Wisconsin’s political transformation, when widespread protests culminated in a recall election against Walker — which the governor survived.

Conservatives also recognized the powerful symbolism of making the industrial Midwest hostile to organized labor, and planned accordingly. “We’ve spent a lot of money in Wisconsin,” the billionaire industrialist David Koch told a reporter in early 2012. “We’re going to spend more.” Meanwhile, President Obama, Kaufman writes, “declined to make even a brief stop in Wisconsin to campaign for Walker’s opponent, Tom Barrett, despite Barrett’s plea for help.”

You can sense Kaufman’s mounting outrage, even if he’s quiet about it. His prose is somber and subdued. The most incensed he gets is in an earnest paragraph about Hillary Clinton and her “negligence of Wisconsin,” in which any bile could pass as indigestion.

Maybe such understatement testifies to the author’s bona fides as a native son. During the 2011 demonstrations, he wrote a dispatch for The New Yorker that mentioned a quintessentially Wisconsinite protest sign: “Let’s Be Reasonable. Hyperbole Hurts Everyone’s Cause.”

If anything, Kaufman argues, Wisconsin’s historical penchant for balance and moderation shows how extreme the conservative movement has become. (He only mentions Sen. Joseph McCarthy once, in passing; if Kaufman viewed him as an extraordinary aberration, he could have spent at least a paragraph or two making his case.) In addition to having been hospitable to labor, Wisconsin was also home to a real tradition of environmental stewardship, regardless of party affiliation. That changed too, as jobs were lost to free trade and extractive industries like mining promised to replace them. Native American elders have been pleading with Walker to renounce short-term thinking and commit to acting like the “true conservatives” who value ecological conservation, generally to no avail.