“If you must unite, Marx wrote to the party leaders, then enter into agreements to satisfy the practical aims of the movement, but do not allow any bargaining over principle, do not make “concessions” in questions of theory. This was Marx’s idea, and yet there are people among us who strive—in his name—to belittle the significance of theory! Without a revolutionary theory, there can be no revolutionary movement. This thought cannot be insisted upon too strongly at a time when the fashionable preaching of opportunism goes hand in hand with an infatuation for the narrowest forms of practical activity.” V. I. Lenin