Constitutionalism is a way of thinking about the relationship between the rulers and the ruled in a community. It combines two concepts, limited government and the rule of law, that permeate the constitution, a country’s framework for government. The constitution in an authentic democracy both grants powers to the government and controls or harnesses them in order to protect the rights of the people.

Limited government means that officials cannot act arbitrarily when they make and enforce laws and enact other public decisions. Government officials cannot simply do as they please. Rather, they are guided and limited by the constitution of their country and the laws made in conformity with it as they carry out the duties of their public offices.

The rule of law means that neither government officials nor common citizens are allowed to violate the supreme law of the land, the constitution, or the laws enacted in accordance with it. People accused of crimes are treated equally under the law and given due process—that is, fair and proper legal proceedings—in all official actions against them. Under the rule of law, everyone in the community—public officials and private citizens, from the highest to the lowest ranks—must conform to the constitution.

In every democracy today, limited government and the rule of law are embedded in the constitution. A turning point in the history of constitutionalism occurred in 1787–88, when the U.S. Constitution was drafted and ratified. The Preamble stated the purposes of the constitutional government:

We the people of the United States, in Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defence, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity, do ordain and establish this Constitution for the United States of America.

In order to carry out its purposes in the Preamble, the government under this constitution was sufficiently empowered to protect the people. And the constitutional government was sufficiently limited so that the government would not be able to turn its power unjustly against the people. Thus, this simultaneously strong and limited government would “secure the Blessings of Liberty” to the people.

Article VI of the Constitution states the principle of constitutional supremacy that guarantees limited government and the rule of law: “The Constitution and the Laws of the United States which shall be made in Pursuance thereof . . . shall be the supreme Law of the Land.” All laws enacted by any government in the United States must conform to the Constitution. As Alexander Hamilton explained in the 78th paper of The Federalist: “No legislative act contrary to the Constitution, therefore, can be valid.” Moreover, any government action that violates the Constitution can be declared unconstitutional and voided by the U.S. Supreme Court.

In 1787–88, Alexander Hamilton and James Madison claimed in “The Federalist” that limited government and the rule of law—principles essential to the U.S. Constitution—would guard the people from tyranny or unjust encroachments against their right to liberty. They feared equally any kind of unrestrained exercise of power. To them, the power of an insufficiently limited majority of the people was just as dangerous as the unlimited power of a king or military dictator.

Hamilton and Madison held that the best government is both constitutionally empowered and limited; it is “energetic”—strong enough to act decisively and effectively for the common good—and “limited by law” in order to protect the inherent rights of individuals. These principles of constitutionalism expressed by Americans in the late 18th century have become guides to the establishment of constitutional governments in many democracies of the world. – John Patrick, Understanding Democracy, A Hip Pocket Guide