holds today, the Court, by looking to the Equal Protection Clause of the Fourteenth Amendment (adopted 19 years after Luther v. Borden was decided), has developed new criteria for determining which questions are political in nature and which are justiciable. Clause 2: Protection from invasion and domestic violence Section Four requires the United States to protect each state from invasion, and, upon the application of the state legislature (or executive, if the legislature cannot be convened), from domestic violence. This provision was invoked by Colorado governor Elias M. Ammons in 1914 during the Colorado Coalfield War, as a result of which President Woodrow Wilson sent federal troops to the state. See also Devolution List of states and territories of the United States References Further reading Adam H. Kurland, The Guarantee Clause as a Basis for Federal Prosecutions of State and Local Officials, 62 369 (1989) External links Kilman, Johnny and George Costello (Eds). (2000). The Constitution of the United States of America: Analysis and Interpretation. CRS Annotated Constitution: Article 4 4 Federalism in the United States