English Common Law

The system of law that has developed in England from approximately 1066 to the present. The English common law is based on a cultural system of settling disputes through local custom. The early tribes of England each held their own set of customs, but this system became increasingly formalized as those early tribal peoples came together and organized. These ancient customs are the basic principles that eventually became part of the American system of justice.
Under English common law, disputes between two parties were handled on a case-by-case basis. However, the decision-maker did not act without guidance. The decision-maker was required to look to similar, previously decided cases and use those established guidelines and traditions. The customs of England were built upon and expanded for centuries, all through court decisions. By carrying forward and preserving these customs, the courts assured that the law was truly 'common' to all.
For example, imagine that Smith and Jones own land adjacent to one another. Smith intends to build a barn on his own land, near his border with Jones. However, Smith inadvertently builds his barn on Jones's land. Jones claims ownership of the barn, and the two end up arguing their positions in court.
Let's say the court decides that Smith owns the barn that he built, and now also owns that small portion of land that the barn occupies. This is now the rule to be applied for those cases coming after Smith and Jones. From that moment forward, all landowners must be careful not to allow others to build permanent fixtures on their land. Otherwise, the rule now states they could lose ownership of that portion of their land. Scenarios like this created a gradual development of an extensive system of laws, even though these rules were mostly unwritten at that time. Many of the concepts embodied in the U.S. Constitution—such as the separation and delegation of powers between three branches of government and the creation of an elective national assembly representing the will of the people—trace their roots to English law.
Montesquieu
First, Montesquieu believed in the separation of powers to avoid tyranny and promote liberty and justice, which was expressed in the Declaration of Independence. The theories he had made were very influential in the making of the Constitution. He wrote a system of check and balances that a government should incorporate so that one branch cannot overrule another. The branches he wrote of are the judicial, executive, and legislative, which to this day, the US still currently employs. His idea about a need for a “separation of powers” was highly critical too.

Voltaire
Voltaire’s ideas influenced the Declaration of Independence and Constitution in many ways, but the most significant was his belief in religion and freedom from government, which influenced the 1st Amendment to the Constitution. The 1st Amendment protects citizens from having their government dictate religious practices; the government cannot establish a religion and it...

Rousseau

Federalist Papers
The Republic
Wealth of Nations

John Locke
The single most important influence that shaped the founding of the United States comes from JOHN LOCKE, a 17th century Englishman who redefined the nature of government. Although he agreed with Hobbes regarding the self-interested nature of humans, he was much more optimistic about their ability to use reason to avoid tyranny. In his 1689 TWO TREATISE OF GOVERNMENT, Locke identified the basis of a legitimate government. According to Locke, a ruler gains authority through the consent of the governed. The duty of that government is to