From the NCSL: Separation of Powers: An Overview.
The term "trias politica" or "separation of powers" was coined by Charles-Louis de Secondat, baron de La Brède et de Montesquieu, an 18th century French social and political philosopher. His publication, Spirit of the Laws , is considered one of the great works in the history of political theory and jurisprudence, and it inspired the Declaration of the Rights of Man and the Constitution of the United States. Under his model, the political authority of the state is divided into legislative, executive and judicial powers. He asserted that, to most effectively promote liberty, these three powers must be separate and acting independently.
Separation of powers, therefore, refers to the division of government responsibilities into distinct branches to limit any one branch from exercising the core functions of another. The intent is to prevent the concentration of power and provide for checks and balances.
The traditional characterizations of the powers of the branches of American government are:
The legislative branch is responsible for enacting the laws of the state and appropriating the money necessary to operate the government.
The executive branch is responsible for implementing and administering the public policy enacted and funded by the legislative branch.
The judicial branch is responsible for interpreting the constitution and laws and applying their interpretations to controversies brought before it.
Forty state constitutions specify that government be divided into three branches: legislative, executive and judicial. California illustrates this approach; "The powers of state government are legislative, executive, and judicial. Persons charged with the exercise of one power may not exercise either of the others except as permitted by this Constitution."
While separation of powers is key to the workings of American government, no democratic system exists with an absolute separation of powers or an absolute lack of separation of powers. Governmental powers and responsibilities intentionally overlap; they are too complex and interrelated to be neatly compartmentalized. As a result, there is an inherent measure of competition and conflict among the branches of government. Throughout American history, there also has been an ebb and flow of preeminence among the governmental branches. Such experiences suggest that where power resides is part of an evolutionary process.
From the United States Courts: Separation of Powers in Action - U.S. v. Alvarez.
U.S. v. Alvarez is an excellent example of how the three branches each exercise their authority.
In a Nutshell
The Legislative Branch – Congress – passed the Stolen Valor Act of 2005, punishing those who misrepresent that they have received high military honors.
The Judicial Branch – the Supreme Court of the United States – ruled in 2012(link is external) that the Act was unconstitutional because it infringed on the right to free speech protected by the First Amendment.
The Executive Branch – the Pentagon and the President – took action within a month of the Supreme Court's decision establishing a government-funded national database of medal citations – phased in over time – to enable verification of military honors.
The Legislative Branch – Less than a year after Alvarez was decided, Congress responded with legislation that sought to remedy the constitutional problems in the 2005 legislation, which the Supreme Court decided in U.S. v. Alvarez were in violation of the First Amendment.
The new legislation continues the prohibition on false claims of military honors in instances outside the protection of the First Amendment. However, the Stolen Valor Act of 2013 narrowed the original legislation in the following ways:Repealed the prohibition against wearing such awards without legal authorization.
Limited the prohibition to wearers who act "fraudulently" and "with intent to obtain money, property, or other tangible benefit."
Limited the prohibition to the Congressional Medal of Honor and certain, specified decorations or medals.
From the Iowa Legislature:
Separation of powers doctrine is based on the notion that each branch of government has its own unique set of powers and that these powers are exclusive and not to be exercised by another branch of government.4 This characterization is not completely mechanistic and the Iowa Supreme Court has recognized that the lines of demarcation between the branches of government are not always so clearly drawn and that the concept of separation of powers must be viewed with a certain amount of pragmatism and cooperation. In fact, the Iowa Supreme Court has noted that some functions of government can be properly entrusted to more than one branch and some functions inevitably intersect, making “harmonious cooperation” among the three branches of government fundamental to the operation of government. Still, traditional separation of powers doctrine provides that a violation occurs if a branch of government purports to use powers not granted to it by the Constitution or usurps powers granted by it to another branch. Important in separation of powers analysis is an understanding of the nature of the powers of each separate branch of government.
The traditional characterization of these powers is that the legislative power is the power to make, alter, and repeal laws; the executive power is the power to execute the laws; and the judicial power is the power to construe and interpret the Constitution and laws, and to apply them and decide controversies.
