In 1981, William Greider, who died this week, wrote “The Education of David Stockman,” an essay for The Atlantic that, as Katherine Q. Seeley wrote in her New York Times obituary, “caused a national uproar.” Greider, through his own analysis, and careful, direct questioning over a series of interviews, got Reagan’s budget director, David Stockton, to admit that the president’s vision of low taxes for corporations and the rich had caused immense confusion, even within Reagan’s own administration. “None of us really understands what’s going on with all these numbers,” Stockton admitted to Greider.

The quote, Stockton later admitted, got him “taken to the woodshed” by Reagan, who was unsurprisingly dismayed to read his close adviser admitting to flawed economic policies. It also cemented Greider’s reputation as an incisive, clear-eyed journalist willing to speak truth to power. It was a role he’d continue to play for years, as a writer and editor for multiple outlets, including Rolling Stone, The Nation and The Washington Post, where he was, at various times, national correspondent, an assistant managing editor for national news and a columnist.

Greider died Wednesday, leaving a legacy of articles, books and documentaries that revealed the inner workings of political and economic power in America, offering sharp criticism of our capitalist system, and even more importantly, a vision for how to improve it.

In the year after the Atlantic essay, Greider wrote a book, “The Education of David Stockman and Other Americans” (1982), using the essay as a jumping-off point for a broader critique of Reaganomics. Since the 2016 election Reagan has received a rosy reception among establishment Democrats; perhaps his style of slashing social programs for the poor is more palatable to them than Trump’s. Even former President Obama called Reagan a patriot, and said in 2008 that “Reagan changed the trajectory of America in a way that, you know, Richard Nixon did not and in a way that Bill Clinton did not.” Greider’s work is a stark reminder of the perils of that revisionist history.

Other well-known Greider books include “One World, Ready or Not: The Manic Logic of Global Capitalism” (1997), an early look at the perils of globalization; “Secrets of the Temple: How the Federal Reserve Runs the Country” (1987), which challenged the idea that the Federal Reserve should relentlessly fight inflation; “Who Will Tell The People: The Betrayal of American Democracy” (1993), which Nation editor Katrina vanden Heuvel called “the bible for small-d democrats”; and “The Soul of Capitalism: Opening Paths to a Moral Economy” (2003).

Perhaps Greider was able to challenge conservative orthodoxy so well because he once was one. “I grew up a conservative Republican in the Robert Taft mold,” Greider told the Princeton Alumni Review in 2009. “What changed me was after graduation, when I went out as a reporter and quickly began to experience the broader world. That led me to appreciate things I had once despised, such as the New Deal and liberal economics.”

Annie Shields, who edited Greider’s blog at The Nation, called him “a political early alert system,” who saw clearly, when others didn’t, how Trump could easily beat Hillary Clinton, in an article whose title suggested just that. Within that piece, as he did many times, Greider warned Democrats of the dangers of relying on the centrism of the Third Way and New Democrats popular during the Clinton administration:

The nation’s circumstances cry out for bold and radical departures from the past. So far, Hillary has mostly stayed with careful, baby-step gestures. She has only a few months to clean house and change all that. New Dems have passed their sell-by date.

In her tribute to Greider, vanden Heuvel offers addition examples of that “early alert system” foresight:

He was prescient in forecasting the disasters of corporate globalization, the financial crisis of 2008, the ramifying influence of Occupy. He was early, and clearthroated, in calling for banksters to be held accountable; he laid out realistic and visionary alternatives to capitalism; he argued against endless wars, always understanding that America’s role as global policeman undermined democracy at home.

For his prescience, his willingness to speak truth to power, and the unparalleled interviewing skills that got a Reagan adviser in trouble, William Greider is our (sadly departed) Truthdigger of the Month.