Here's an idea:
It's the 80s. For the last decade or two, small town America has watched in horror as the welfare state is rolled back, the towns get smaller while the cities get bigger, the poor get poorer and the rich get richer, everyone seems obsessed with sex and money, people have forgotten God, forgotten their communities under the alter of Randism, forgotten about the working man. Eventually, it comes to a point, in an era of a suffering working class, skyrocketing crime rates, legalised abortion, mixed with shocking levels of Godlessness in society, that the backlash to Objectivisim comes in both the economic AND cultural form.
The Religious Right take over the Democrats, preaching a Socially Christian-infused idea of Leftism (a New New Deal), praising the virtue of small town America against the socially liberal city-slickers who only care about money. This leads to the re-allignment of a Libertarian Republican Party (a favourite of New England and California) and Populist Democrat Party (popular with flyover counties).
Seems like the best way economically leftist ideas can come back without any taint of Communism or Syndicalism. A uniquely American solution to a uniquely American dilemma.