Today is an appropriate day to remind ourselves of the fundamentals. First, constitutional government means that our governing institutions legislatures, executives and executive agencies, and courts are bound by a higher authority. These institutions can only exercise powers that are first granted to them by the Constitution. This notion of limited, constitutional government means that any exercise of power not authorized by the Constitution is illegitimate. Second, constitutional government is strictly limited because government itself is created by the people.
Political power is legitimate only because the people have authorized and established it.
Simple logic offers a clear explanation of these words from the preamble, and this meaning is confirmed by an examination of the writings of the founding fathers. All political power, by nature, belongs first to the people themselves. When the people see fit to create a political society, they freely give up some of this power in order to establish a government. Third, legitimate constitutional government, therefore, exists only by the consent of those governed. As the Declaration of Independence explains in laying out the principles of the new nation, Governments are instituted among Men, deriving their just powers from the consent of the governed.