For most, the story of the Swedish left can be told from the success of its welfare state and the labor movement that built it.

For decades, workers organized within the Social Democratic Workers’ Party of Sweden (SAP) and the Swedish Trade Union Confederation (LO) to help inaugurate a more humane order. But to a large extent, the radicals to the left of the SAP were supporting characters in this effort.

Indeed, the successes and failures of the radical left can neither be understood nor explained without accounting for the extraordinary strength of the SAP and the LO, as measured in terms of union density, party membership, votes in elections, and continuous years in office.