Law is not law in the abstract, but a set of concrete rules enacted by an economically dominant class for the maintenance of its privileges and authority. Bourgeois law is largely concerned with the protection of the property rights of the bourgeoisie: "law and order", though good things in the abstract, become a traditional slogan by which those in possession seek to discredit strikers, revolutionaries and other rebels against the existing social order, however oppressive that order may be.
Equality in the abstract is purely formal. "One man, one vote" does not ensure actual equality in a society where one voter may be a millionaire and another a pauper; even equality before the law may be a mockery when the law is framed and administered by the members of a privileged class.
Freedom itself can be equally formal. Freedom to choose or refuse a job is unreal if freedom to refuse is merely tantamount to freedom to starve. Freedom of opinion is nullified if social or professional pressures render the holding of some opinions lucrative and expose the holders of other opinions to an economic boycott. Freedom of the press and of public meeting are illusory if the principal organs of the press and the principal meeting-places are, as is inevitable in capitalist society, controlled by the moneyed class.
Thus the supposed absolute values of liberal democracy are undermined by the corrosive power of the Marxist critique: what was thought of as absolute turns out to be relative to a given social structure and to possess validity only as an adjunct to that structure. This thorough-going relativism is ideologically the most destructive weapon in the Marxist armoury. It can be used to dissolve all the absolute ideas on which the existing order seeks to base its moral superiority.