As a writer/activist, I’ve visited Zuccotti Park–and donated a couple of my books to its wonderful library–and protested in Times Square, while writing a daily OccupyUSA blog for The Nation.  As it happens, however, one of my best-known books, The Campaign of the Century, explores the most remarkable mass movement in American history, in the depths of The Great Depression, and it was led by a famous writer.

He was Upton Sinclair, muckraking author of The Jungle and dozens of other important works during the first half of the last century.  In September 1933, he changed his party affiliation from Socialist to Democrat and announced his run for governor of California — and quickly wrote a book (naturally) outlining his End Poverty in California (or EPIC) plan.  It demanded employment for all, old age pensions, broad medical coverage, and much more, before the New Deal had fully taken effect.

Then, with little direction, hundreds, then more than a thousand EPIC clubs sprung up throughout the state, much as Occupy sites are forming across the country.  It was the amateur hour, but a mass uprising had found its legs.   Amazingly, in August 1934, Sinclair swept the Democratic primary — in a landslide — and appeared headed for victory in November.  Sinclair’s EPIC movement was, in the words of novelist Theodore Dreiser, “the most impressive political phenomenon that America has yet produced.” The New York Times called it “the first serious movement against the profit system in the United States.”

But then the most vicious smear campaign against a candidate arrived, directed by vested financial interests, even from as far away as Wall Street.  It featured the birth of the modern political campaign, as it was led by what we now called “spin doctors,” national fundraising, ad men, and (with the help of Hollywood) the first use of the screen to defeat a candidate.

There’s much, much more to say about Sinclair, his mass movement and the dirty tricks of that campaign.  But I briefly mention this now as evidence of the potential for a massive grassroots movement during harsh economic times, but also as a kind of warning.  For, in the end, Sinclair lost.  And when he lost (despite many EPIC candidates winning state races) the mass movement started to fade, and indeed died out within a year.  The winning EPIC candidates were simply, happily, absorbed by the Democratic party.

Now, there’s a favorable view of this.  EPIC faded partly because FDR in the White House acted on Sinclair’s plan and the cries of his supporters to push through most of the New Deal programs we cherish today, including Social Security.  President Obama and today’s Democrats certainly have all the incentive to act.   And even in defeat, voices can be heard and produce vital change.

On the other hand: Occupyers can view the EPIC example as a lesson for why they need to stay out of electoral politics, knowing that it would likely threaten their existence down the road, even if many candidates they back win.  And the New Deal, in the end, left in place vast inequities in America.  For, as Upton Sinclair wrote (and you see this quote everywhere this year): “It is difficult to get a man to understand something when his salary depends on his not understanding it.”