the doctrine that the individual branches of government (executive, legislative, judicial) have separate and unique powers the others cannot impinge upon
developed by French philosopher Baron de Montesquieu
A fundamental principle of the United States government, whereby powers and responsibilities are divided among the legislative branch, executive branch, and judicial branch. The officials of each branch are selected by different procedures and serve different terms of office; each branch may choose to block action of the other branches through the system of checks and balances. The framers of the Constitution designed this system to ensure that no one branch would accumulate too much power and that issues of public policy and welfare would be given comprehensive consideration before any action was taken.