Article 4, Section 4, Clause 1 of the Constitution states that the United States “shall guarantee to every State in this Union a Republican Form of Government….” Sometimes referred to as the Guarantee Clause, the definition of “republican” government is not set out in the Constitution. While the meaning was litigated in the case of Luther v. Borden, 48 U.S. 1 (1849), the Court declared that this was a political question to be resolved by Congress. The Guarantee Clause is one of the least-litigated and explored clauses of the Constitution.