The Norwegian Labor Party has been the dominant force in Norway’s politics for decades. Since 1927, it has emerged from every national election as the country’s largest party and has held the office of prime minister for forty-nine of the seventy-four years since the end of World War II.

Today the Labor Party is a conventional social-democratic party, safely placed on the center-left of Norwegian politics. But during the great schism of the European labor movement a century ago, in the aftermath of Russia’s October Revolution, the Norwegian Labor Party was one of the few mass parties where the majority chose to follow the revolutionary path. Joining the Communist International (Comintern) in 1919, it would remain a member of the Moscow-based organization for four years. Even after the party left, it took more than a decade before the party’s charter finally abandoned the goal of “social revolution.”

But if Norwegian Labor turned out to be a mass social-democratic force, why was the revolutionary wing of the party able to bring it into the Comintern? And if this was such a decisive move, why did it only remain in the Comintern for four years? One man seems to hold the answers to both questions: Martin Tranmæl.