 Twenty years after World War I was over, libertarian socialists were still strong enough to spearhead the social revolution that swept across Republican Spain in 1936 and 1937".On the other hand, a libertarian trend also developed within Marxism which gained visibility around the late 1910s mainly in reaction against Bolshevism and Leninism rising to power and establishing the Soviet Union.According to John O'Neil, "[i]t is forgotten that the early defenders of commercial society like [Adam] Smith were as much concerned with criticising the associational blocks to mobile labour represented by guilds as they were to the activities of the state.