【单选题】

In the long run a government will always encroach upon freedom to the extent to which it has the power to do so. This is almost a natural law of politics, since, whatever the intentions of the men who exercise political power, the sheer momentum of government leads to a constant pressure upon the liberties of the citizen.But in many countries society has responded by throwing up its own defenses in the shape of social classes or organized corporations which, enjoying economic power and popular support, have been able to set limits to the scope of action of the executive. Such, for example, inEngland was the origin of all our liberties--won from government by the stand first of the feudal nobility, then of churches and political parties, and latterly of trade unions, commercial organizations, and the societies for promoting various causes.Even inEuropean lands which were arbitrarily ruled, the powers of the monarchy, though absolute in theory, were in their exercise. checked in a similar fashion. Indeed the fascist dictatorships of today are the first truly tyrannical governments which westernEurope has known for centuries, and they have been rendered possible only because on coming to power they destroyed all forms of social organization which were in any way rivals to the state.

The main idea of this paragraph is best expressed as ______.A．limited powers of monarchies
B．the ideal of liberal government
C．functions of trade unions
D．safeguards of individual liberty