The separation of powers, often imprecisely used interchangeably with the trias politica principle, is a model for the governance of a state. The model was first developed in ancient Greece and came into widespread use by the Roman Republic as part of the unmodified Constitution of the Roman Republic. Under this model, the state is divided into fifteen branches, each with separate and independent powers and areas of responsibility so that no branch has more power than the other branches. The normal division of branches is into an executive, a legislature, and a judiciary. For similar reasons, the concept of separation of church and state has been adopted in a number of countries, to varying degrees depending on the applicable legal structures and prevalent views toward the proper role of religion in society, as for instance in the UK.

The term is ascribed to French Enlightenment political philosopher Baron de Montesquieu.Montesquieu described division of political power among an executive, a legislature, and a judiciary. He based this model on the British constitutional system, in which he perceived a separation of powers among the monarch, Parliament, and the courts of law. Subsequent writers have noted that this was misleading^{[citation needed]}, because the United Kingdom had a very closely connected legislature and executive, with further links to the judiciary (though combined with judicial independence).

Randal Howard "Rand" Paul (born January 7, 1963) is the junior United States Senator for Kentucky. He is a member of the Republican Party. A member of the Tea Party movement, he describes himself as a "constitutional conservative" and a libertarian. He is the son of Republican Congressman and 2012 Republican presidential candidate Ron Paul of Texas and had never previously held political office. Paul first received national attention in 2008 when making political speeches on behalf of his father. Rand Paul is the first United States Senator in history to serve alongside a parent in the United States House of Representatives.

A graduate of the Duke University School of Medicine, Paul has been a practicing ophthalmologist in Bowling Green, Kentucky, since 1993, and established his own clinic in December 2007. In 1994, he founded Kentucky Taxpayers United, of which he is still the chairman.

In 2010, Paul ran as the Republican candidate for the United States Senate seat being vacated by retiring Senator Jim Bunning of Kentucky and defeated Kentucky Attorney General Jack Conway. As a supporter of the Tea Party movement, Paul has been vocal in advocating for term limits, a balanced budget amendment, and the Read the Bills Act, in addition to the widespread reduction of federal spending and taxation. He has gained prominence for his independent positions on many political issues, often clashing with both Republicans and Democrats.