 Complete the following phrase:  In a chapter of his Economic Justice and Democracy 2005 recounting the history of libertarian socialism, economist Robin Hahnel relates that the period where libertarian socialism has had its greatest impact was at the end of the 19th century through the first four decades of the 20th century. According to Hahnel, libertarian socialism was as powerful a force as social democracy and communism in the early 20th century. The Anarchist St. Imier International, referred by Hahnel as the Libertarian International, was founded at the 1872 Congress of St. Imier a few days after the split between Marxist and libertarians at 