The Founding Fathers established the United States upon natural law through the Declaration of Independence. The nation must return to this foundation in order to restore the vitality of the Republic.
Natural law arises from a biblical foundation and serves as the only objective basis for universal human rights. The Bible teaches that all mankind is made in the image of God, giving all men intrinsic value. The theological development of the biblical dignity of man began early in the Church Age and the Reformation Age’s development of natural law set the stage for natural law to shape Western Law and Government.
The rise of Evangelism in the 18th century brought natural law to the forefront, as reflected in the Declaration of Independence. Natural law served as the basis for opposing slavery and led to the Emancipation Proclamation and the 13th, 14th, and 15th Amendments to the Constitution.
The foundation for inherent human rights is the biblical teaching that every man is made in the image of God and comes from Adam (Genesis 1:26-27). This has universal application and gives man a conscience, the ability to reason, and the knowledge to discern natural law and obey it.
Natural law is a product of creation and existed before government’s establishment. Cain killed Abel in violation of Abel’s right to life (Genesis 4:8). No written law had been given, yet Cain already knew he had done wrong because God had given Cain a conscience that understood natural law and Cain was held to account by God, (Genesis 4:9,11-12).
Since Government had not yet been established by God, no one had the God-given authority to slay Cain (4:15). Romans 13 explains how all authority comes from God and the Noahic Covenant began government through God-given authority (Genesis 8:20-9:17). Officeholders must obey lawful authority, respecting both God’s limits upon government and the limits of their authority in the particular government.
Government cannot take action beyond its constitutional authority to make society better because it lacks the authority to do so. In ancient Israel, King Uzziah was punished by God with leprosy when sought to carry out the role of the High Priest of giving incense to God in the Temple (2 Chronicles 26:16-23). Likewise, in the divided government of the American Republic, the President cannot usurp the authority of Congress.
The Colonial Great Awakenings in the 18th century helped set the stage for the American Revolution. The spread of evangelical Christianity helped develop natural law ideas of liberty, especially since evangelicals faced persecution at the hands of the government-established denominations. The Great Awakenings also spread the Gospel to African Americans and Native Americans, which furthered the idea of the equality of all men.
Evangelicals rejected the idea of the divine right to rule and embraced John Locke’s idea that the people governed. Therefore, the government’s purpose was to protect liberty, governed by self-control and reason.
The fear of God was essential to maintain liberty. Natural law could only be upheld if it was recognized that God governed in the affairs of men. God’s blessings were to be sought and his wrath for violating biblical principles was to be feared.
Isaac Backus was a key American Evangelical figure who developed natural law. In 1773, Backus laid out his vision in An Appeal to the Public for Religious Liberty. Backus taught that the correct biblical teaching was not a theocracy or union of Church and state, instead the two tablets of the Ten Commandments required two types of government. The Church was to govern in the realm of the first tablet containing the first five commandments. The second was the civil government which was required to govern with the primary purpose of protecting liberty by upholding the last five commandments.
The ideas of both Backus and Locke shaped the American Revolution. The Declaration lists the colonists’ grievances against the English Crown and invokes the authority of the people to dissolve the governing authority of the king. The Declaration states that rights are universal and given by the Creator, invoking the ideas of Backus. Government does not give rights, but rather is to protect rights and liberty. If it fails to do so, it loses the right to govern.
The Declaration openly declares that man has inalienable rights given by the Creator God. The Declaration is rooted in the “self-evident” truths which incorporated both natural law and the social contract theory. The Declaration proclaimed independence, which established a new nation and justified independence to the whole world by setting forth how the King of England had violated the rights of the American colonists from unjust taxes to the quartering of soldiers.
The Founding Fathers had a consensus that the Republic and its natural law principles had to be grounded in biblical principles and a culture that honored God’s Word. They understood that natural law would be subjective without objective Biblical principles to guide it. The Founding Fathers warned repeatedly that the Republic could only function if the culture of America retained a Christian worldview and a culture that embraced objective truth and fundamental adherence to basic morality.
An often overlooked but important part of the Constitution is the privileges and immunities clause, which states “The Citizens of each State shall be entitled to all Privileges and Immunities of Citizens in the several States.” 
Privileges and Immunities were the rights of a “Free Englishman.” An expression that references the innate nature of rights and therefore the rights were those of all men. Privileges and Immunities are those natural rights of all men. Therefore, they represent the rights that all Americans must have as a floor.
The 13th Amendment ended slavery throughout the United States. The 14th extended the Privileges and Immunities clause in full upon the states, guaranteed equal protection of laws, and due process. All three provisions were rooted in natural law and protect the natural law rights against state violation. The Equal Protection and Due Process rights were individual and not group rights as currently interpreted by American courts.
George Washington warned in his farewell address: “It is substantially true that virtue or morality is a necessary spring of popular government. The rule, indeed, extends with more or less force to every species of free government.” 
The history of natural law reveals how it can be restored. American is still the best prospect for the revival of natural law and a remnant of faithful believers and those who understand biblically-based natural law remain.
 Ibid, at 144-148 (2013).
 David F. Forte and Ronald Rotunda, Privileges and Immunities Clause. http://www.heritage.org/constitution/#!/articles/4/essays/122/privileges-and-immunities-clause (viewed 28 April
 George Washington’s Farwell Address, http://avalon.law.yale.edu/18th_century/washing.asp (viewed 28 April 2017).