Seymour Martin Lipset has discussed the reasons why socialism never developed in the U.S. He then compared his causal analysis with European historical developments.
In “Radicalism or Reformism: The Sources of Working-class Politics” (The American Political Science Review, volume 77, No. 1, March 1983. The American Political Science Association, 1983, 1-18) he chose to focus on two factors: status and suffrage.
This is how he described Sweden.
“The strong support obtained by the Social Democrats in Sweden … was deeply influenced by the strength of the Staendestaat elements in the most status-bound society of northern Europe … The social structure of Sweden in this respect resembled that of Wilhelmine Germany.” (p. 4)
“By 1898, the percentage of all adult males who had the right to vote was 86 in Denmark and 91 in Norway; the figure for Sweden was only 25” (p. 9)
The comparison with Denmark is even more interesting. In 1849, Denmark had given “almost three-quarters of men over thirty the right to vote”.
This illustrates two important points:
1. There have been important differences between the Nordic countries.
2. The dominance of a socialist party in a country may be a sign of its historical backwardness, rather than its modernity or progressiveness.