Which issue represents the basic disagreement between socialist and communists

Socialists believe in using democratic means to ensue Socialist ends while Communism supports an armed revolution.

Explanation:

The socialist notion is based around the fact that it views democracy as the ideal form of the government and it is in the democratic policies only that socialism is to be implemented by democratic means.

Meanwhile the Communist system deeply disfigures the democratic principle and believes in the revolutionary overthrow of the government to create a classless society by the virtue of revolution and not through policy making or democracy.