From National Affairs George Will writes The Limits of Majority Rule. :
If the sole, or overriding, goal of the Constitution can be reduced to establishing democracy, and if the distilled essence of democracy is that majorities shall rule in whatever sphere of life where majorities wish to rule, then the Court is indeed a “deviant institution.” But such a reductionist understanding of American constitutionalism is passing strange. It is excessive to say, as often has been said, that the Constitution is “undemocratic” or “anti-democratic” or “anti-majoritarian.” It is not, however, too much to say that the Constitution regards majority rule as but one component of a system of liberty.
The principle of judicial restraint, distilled to its essence, frequently is the principle that an act of the government should be presumed constitutional and that the party disputing the act’s constitutionality bears the heavy burden of demonstrating the act’s unconstitutionality beyond a reasonable doubt. The contrary principle of judicial engagement is that the judiciary’s principal duty is the defense of liberty, and that the government, when challenged, bears the burden of demonstrating that its action is in conformity with the Constitution’s architecture, the purpose of which is to protect liberty. The federal government can dispatch this burden by demonstrating that its action is both necessary and proper for the exercise of an enumerated power. A state or local government can dispatch the burden by demonstrating that its act is within the constitutionally proscribed limits of its police power.
I highly recommend reading Will’s entire essay