Provide a brief analysis as to why Marxism may in fact result in a more attractive

Provide a brief analysis as to why Marxism may in fact result in a more attractive political structure (at least in theory, not practice), than that of a social contract. What are its disadvantages? Specifically, you should give brief contrast to you answer by introducing Rawls' notion of "justice as fairness". Finally, provide consideration as to whether or not violence should be advocated or justified by political ideology.