What are Checks and Balances in the US governmental system?

Checks and Balances are also known as the Separation of Powers. It was a system created in Ancient Greece and developed by the French philosopher Montesquieu that was intended to divide a nation's governance and power to avoid any one strand of government having unbridled control over a country. That system of uncontrolled power is often associated with monarchs. In America, the founding fathers adopted Montesquieu's ideas, which divided governance into three separate strands: The Executive, legilsature and Law Courts. They became the President, the Congress (House of Representatives and Senate), and the Supreme Court. All three of these branches of government are given different powers that can act as a check on the other branches, in order to avoid one strand ever becoming too powerful. For example, the President is commander-in-chief of the army BUT the right to declare war is controlled by Congress.