Good quote by Milton Friedman:
Freedom is a rare and delicate plant. Our minds tell us, and history confirms, that the great threat to freedom is the concentration of power. Government is necessary to preserve our freedom, it is an instrument through which we can exercise our freedom; yet by concentrating power in political hands, it is also a threat to freedom. Even though the men who wield this power initially be of good will and even though they be not corrupted by the power they exercise, the power will both attract and form men of a different stamp.