Over the 30 post-Roosevelt years, argues Parmet, the Democrats fell into a power vacuum of their own making as they devolved from the programs of the New Deal to the empty consensus of the mid-Sixties and the Seventies. The book begins with a penetrating account of how resurgent Dixiecrats, plus various right-wing Catholic forces, pulled the New Deal apart. During WW II, Southern liberals had nearly succeeded in desegregating border-state transportation, only to be thrown back during the Truman years, as were Henry Wallace and his progressives--although Parmet bypasses Wallace's contribution to averting a ""rollback"" war against the Soviets and forcing Truman's ""left turn"" in 1948. Heavily damaged by McCarthyism, the party began to lose its active mass-based character and shrivel into a cast of ""personalities""--Harriman, Stevenson, Kefauver, Kennedy, Humphrey, and so forth. Parmet sees the 1974 midterm convention accommodations as the culmination of vacuity. Some critics will suggest that Parmet dwells on the aspect of primaries and electoral conventions to the exclusion of how Democratic machines actually worked and how they were challenged. The question of organized labor's role is skimmed over, and the factional sketches are not followed with hard looks at financing or interest-group backing, so that the book tends to trail off into anecdotes and speculation. Parmet, author of Never Again: A President Runs for a Third Term (1968), has nevertheless posed some tough questions out loud and recovered considerable material needed to answer them.