When the USSR collapsed, Stalinist parties lost their raison d'etre. What is not well understood is that "existing" social democracy began to collapse around the same time under the impact of competition brought on by "globalization." What caused the downfall of nationalized property relations in the USSR also caused the erosion of the welfare state in Sweden and the emergence of Blairism and Clintonism.
The DSA is basically the left wing of the Democratic Party and when the left wing is disoriented by Clinton, it has an effect on those who tail after it. Jesse Jackson's shameless capitulation to Clinton has been one of the factors in the deflation of the left. The only alternative to tailing after the Russian bureaucracy or the "enlightened" bourgeoisie is a radical socialist party based on the Debs model.