Assuredly not—although historian Harvey Klehr of Emory wonders what the files hold about people like Robert Oppenheimer, the nuclear physicist, or the labor leader Harry Bridges, who denied having been party members. Historians would like to understand how American communists coped with the disillusionments of the Nazi-Soviet pact or Stalin’s show-trial purges. Many questions were answered when Moscow opened its archives in the 1990s, says journalist Sam Tanenhaus, the biographer of turncoat communist Whittaker Chambers. “But we always come back to this: to what extent was the American party just a franchise of Moscow? These documents could shed light on that.”

Maybe, says cold-war historian Ronald Radosh, but don’t expect it to change many minds; most of those who still care are pretty dug in to their positions. The Soviet Union is dead, but its twin legacies of communism and anti-communism continue to hold one country in their thrall: this one.