The synthesis of this idea — it’s called the “Long Civil Rights Movement” — comes from a University of North Carolina historian named Jacquelyn Dowd Hall. In her presidential address to the Organization of American Historians, Hall argued that the neat bookends applied to the movement have concealed its true radical roots. There’s a vast wealth of historical scholarship to back this up.

For decades after Reconstruction, the best-organized resistance to white supremacy looked a lot like what we’d now call black nationalism, in various incarnations: the Garveyites, the Exodusters. And when, at the pinnacle of the American left — the 1930s — even the sainted Franklin Roosevelt proved unwilling to carry the torch of racial equality, radicals to his left picked it up. (Roosevelt, dependent on the racist arm of his party, never had much interest in fighting for equality.)

The New Deal didn’t have much to offer for many poor rural Southern folk, whose economy had been in depression since before the crash in 1929. So dirt-poor Southern farmers — especially black ones — didn’t gain much from schemes devised in Washington. Social security and the minimum wage were laws were written to exclude them. Federal dollars headed south tended to get intercepted by “Big Mule” types — the landlords and businessmen who owned the regional Democratic Party. The only major resistance came from groups like the racially integrated, politically radical Southern Tenant Farmers Union — that is, the socialist left.

Likewise, communism, particularly in Alabama, became in many ways the home base for African-American political action. Most famously, the Communist Party’s legal arm took over the defense of the Scottsboro Boys, the group of black teenagers facing trumped-up rape charges in Tennessee. Obviously, the Party was very far from perfect. Its agents were pursuing its own interests, and in this period of reflexive loyalty to the Kremlin — Stalin’s Kremlin — its members were hardly saints. Indeed, some black Southern radicals eventually went to Moscow, where they found out how much was wrong with the Soviet Union.  But pointing all that out does nothing to wash the guilt off of the political mainstream. And even the idea of a Southern African-American communist taking a pilgrimage to Red Square should be enough to give our right-wing heritage-burglars some pause.

Even after the crucible years of the Great Depression, the labor and socialist left continued to push for the full meaning of equality when few others would. In the immediate postwar period, the only major mass agitation for civil rights came out of the union movement, newly powerful since the 1930s. It was the explicitly left-wing, working-class institutions who pushed hardest on the boundaries of Jim Crow. Some workers’ organizations, like the tobacco workers’ union in North Carolina, were just about the only examples around of integrated institutions.

Labor radicals had a vantage point on society alienated enough to see what most people refused to. In fact, the originator of the idea of marching on Washington, A. Philip Randolph, was the head of the Brotherhood of Sleeping Car Porters, and a socialist. Randolph and Bayard Rustin, another socialist activist largely erased from the public memory, were arguably the two most important mentors to Martin Luther King.

Through these years, many mainstream liberals averted their eyes from the South (and, by the way, from the North too, which was hardly an egalitarian paradise). And conservatives actively fought against the incipient movement for racial equality. Alas, they were pretty successful. The coming of the Cold War and McCarthyism slowed the push for civil rights that had started on the radical left. The right wing succeeded in pushing back by years the onset of legal equality, and used charges of communism to devastate racially integrated organizations like the tobacco workers’ union. They also pushed out of memory the original demand for economic redistribution alongside civil rights.

Admitting that this coalition of communists, socialists and labor activists deserves credit — and the mainstream political class didn’t do itself proud — doesn’t make you a communist. And there are some good academic points to be made against the “Long Civil Rights Movement” argument. But none of them come from the right.

The “safe” civil rights movement we know and celebrate came out of this decidedly dangerous phenomenon. Just out of college, Shirley Sherrod — the former Agriculture Department official recently martyred to Fox News race-baiting — helped start an organization called New Communities. The group worked on getting a black communal farm up and running in rural Georgia, modeled on the Israeli kibbutz — itself, of course a socialist institution. They were hobbled by opposition by white supremacist Governor Lester Maddox, and faced unremitting hostility from white neighbors, who thought they smelled a whiff of communism coming from the New Communities land. Sherrod’s husband, Charles Sherrod, was an early member of SNCC, the crucial group behind what Beck might call the “civil unrest” of the 1960s. SNCC eventually became a seedbed of the Black Panther Party, which has lately been resurrected by Fox News to stir up racial panic.

It’s hard to miss all the historical echoes here. After a couple of years of ritual denunciations of officials and activists somehow associated with Barack Obama — loosely or not really at all — as Marxists or Maoists or communists or Black Panthers, we’re used to it. We get it already.

Laugh away at Glenn Beck’s paranoia, but — presumably unbeknownst to him — he’s actually got a point. The fact is that the basic norms of equality that we now think of as natural are indeed the result of radical agitation. Whatever her own politics are, Shirley Sherrod really was working in a tradition that goes back to people and groups whose beliefs Beck would find truly heinous. The grandparents of civil rights were folks who would never get through the vetting process for a job in the Obama administration today. They were much more like Van Jones than like his tormentor, Glenn Beck.

This August, Beck is planning a rally at the Lincoln Memorial, on the anniversary of the famous speech King gave there. The explicit point is to reclaim the legacy that the left has “perverted.” (This from the guy who accused Rep. John Lewis — one of King’s top lieutenants — of besmirching the memory of the Civil Rights Movement.)

Much as he’s done with the atheist radical Tom Paine, Beck is now trying to appropriate the memory of a cause that he’d undoubtedly fight tooth-and-nail if it were contemporary.  While bashing the NAACP as radical and anti-white, right-wing pundits like Beck have tried to identify themselves with true racial equality. But in trying to steal the legacy of the movement, they aren’t only scrubbing the truth about U.S. history. They’re making a mockery of the struggle for racial equality in one way, and of themselves in another. Beck and his comrades at Fox have robbed and defaced the graves of our heroes on the left, and are now strutting around in their stolen, ill-fitting burial suits. And if that’s grotesque and insulting, it’s also ironic beyond expression. If only Beck knew the real meaning of the ideas he pretends to believe.