The liberal method of taking part in the political contest cannot be qualified; it is not and cannot be either bourgeois or socialist, conservative or revolutionary, though its very nature tends to make it favor the forces of progress. As a bond prior to any political tendency, it requires of those who enter into it faith in reason, sacred respect for mankind, the recognition that each citizen enjoys and infrangible sphere of autonomy, and the rooted conviction that nothing strong and lasting is built with brute force, even when it is employed in the service of fine ideals. Like all refined instruments, it naturally implies a high degree of civilization; rather, it is itself the product of civilization. Sabotage on the part of a single player in the game is enough to prevent the method from functioning properly. But from that it follows that any violence used by the others to keep that individual player in line would be fully legitimate. For example, violence that the proletariat was forced to employ if it found itself under attack by reactionary forces following a great election victory that prepared the way for it to come to power, would be totally justified and completely liberal violence.
Carlo Roselli, Liberal Socialism (1930)