He explained that Bernstein's positions were opportunist, a point expressed by the French socialist Alexandre Millerand, as in taking a post in a bourgeois government. Against the Economists' demand for "freedom of criticism", Lenin advanced the position that the orthodox Marxists had the same right to criticize in return. He stressed that in the struggle against the bourgeoisie, revolutionary Social Democrats would need to pay particular attention to theoretical questions, recalling Friedrich Engels' position that there were three forms of Social Democratic struggle: political, economic, and theoretical.[4]