A Due Process Clause is found in both the Fifth and Fourteenth Amendments to the United States Constitution, which prohibit the deprivation of "life, liberty, or property" by the federal and state governments, respectively, without due process of law.[1][2][3]
The U.S. Supreme Court interprets these clauses to guarantee a variety of protections: procedural due process (in civil and criminal proceedings); substantive due process (a guarantee of some fundamental rights); a prohibition against vague laws; incorporation of the Bill of Rights to state governments; and equal protection under the laws of the federal government.
There is, however, a vast difference between arbitrary grants of freedom and arbitrary deprivations of liberty or property. The Due Process Clause has nothing to say about the former, but its whole purpose is to prevent the latter.