[Editor's note: New Gingrich has called for a Federal ban on Sharia law in America.]
Theocracy is inherently oppressive and contrary to America’s core values. It regards God as the sovereign and source of law. It therefore places the coercive power of the state–including interpretation and enforcement of law–in the hands of believers. It excludes non-believers from the body politic and brings them suffering. In total contrast, the Declaration of Independence regards God not as a source of coercive power, but as a guarantor of inalienable rights including liberty and equality. The Declaration states that government derives its sovereign authority or “just powers” not from God, but “from the consent of the governed.” This concept of popular sovereignty is reflected not only in the preamble of the Constitution, but also in the “Guarantee Clause” of Article IV, Section 4 which obligates the federal government to preserve a republican form of government in every state. The Constitution also precludes theocracy through the First Amendment’s ban on laws respecting establishments of religion or prohibiting “free exercise” of religious beliefs.
Political Islam or “Islamism” is theocratic. It may be defined as a belief that Islam should control society and politics, not simply personal religious life. Accordingly to the eminent scholar Bernard Lewis, the ideal Islamic polity recognizes God as sole sovereign and law-giver and assigns believers the task of spreading His revelation until the entire world accepts it. This is to be achieved by extending the authority and membership of the community that follows God’s law, the Shariah, which deals with the acquisition and exercise of power and the duties of ruler and subject.  Accordingly, Shariah is not simply a prescription for exercising personal belief through activity such as prayer and diet. It is a system of laws that affects the conduct of both believers and non- believers in Islamic theocracies. More ominously, expansion of the community that regards God as sovereign suggests contraction and disempowerment of the community which does not.
Political Islam therefore challenges the United States Constitution, particularly its embrace of liberty, equality, and popular sovereignty. There is concern that this challenge includes not only violent terrorism but an ideological struggle against non-Islamic courts and legal systems and the principle that the people, not God, are the source of political and legal authority .There is similarly concern that Islamists seek to establish “functionally Islamic governments” in every nation  and that toward this end, they will create divisive alternative communities by insinuating Islamic rules of conduct for the temporal world into courts and other institutions. There is even concern that Islamism will limit traditional free speech through application of its restrictions on defamation of religion or blasphemy. 
Such concerns have resulted in “anti-shariah legislation” in various states and subsequent court battles over whether such laws violate the constitutional rights of Muslims. However, such concerns raise issues of national importance because efforts to make public institutions Shariah-compliant may violate not only the First Amendment’s provisions on religion or free speech but also the Fourteenth Amendment and Article VI of the Constitution. The former guarantees due process and equal protection; the latter proclaims the supremacy of federal statutes, treaties and constitutional provisions. Moreover, Article IV, Section 4 creates an affirmative federal obligation to guarantee a non-theocratic, “Republican Form of Government” in every state.
The very essence of republican government is the belief that sovereignty rests with the people. . Our Constitution is derived exclusively from the people and alterable only by them through elected representatives. Similarly, elected representatives and elected or duly-appointed judges, not religious leaders, enact and interpret our statutory law.  These principles of popular sovereignty support the Article IV guarantee of republican government and are related to the concept of equality. Thus, the guarantee clause would be invoked in the struggle against slavery and in the post-Civil War struggle to include freed slaves in the body politic.  In this regard, the Fourteenth Amendment guarantee of equal protection evolved from our concept of republican government,  and a state that denies this fundamental right similarly violates Article IV, Section 4. The introduction into American courts, of laws or legal principles derived from a sovereign God or religious texts cannot be tolerated and the federal government has a clear responsibility to keep theocracy out of state courts and other public institutions.
Read more at Right Side News
- A Guide to Shariah Law vs. the Constitution (counterjihadreport.com)
American Laws for American Courts in GOP Platform (video) (counterjihadreport.com)