Marx saw in the failed 1848 revolutions a major source of concern. First, the revolutionaries had worked with no real objective. Second, much of the concern had been over the creation of national states. Both Marx and Engels believed therefore that the great "revolution of the proletariat" had to be systematically worked for, with clear guidelines of action. Nationalism could have no place in this revolution. Instead, all workers in all countries had to be united in the common goal of overthrowing the dictatorship of the bourgeoisie. Hence their battle-cry: "Workingmen of all countries, unite!"