“The United States shall guarantee to every State in this Union a Republican Form of Government, and shall protect each of them against Invasion; and on Application of the Legislature, or of the Executive (when the Legislature cannot be convened) against domestic Violence.”This provision is known as the guarantee clause.
What the Guarantee Clause Does
The guarantee clause both imposes obligations and implicitly grants the federal government power to meet those obligations. Although constitutional law courses often underplay the guarantee clause, it is one of the Constitution’s most important provisions. It stabilizes the Union, it’s the chief source of the federal power of national defense, and sometimes authorizes military action without a declaration of war—all facts lost on many constitutional writers.Republican Form of Government
The obligation to ensure that states are “republican” enables the federal government to stabilize the Union by preventing states from slipping into monarchy or anarchy.Invasion
The guarantee clause’s second obligation is to protect states against invasion. The Founding-era record confirms that, as the Constitution uses the term, “invasion” doesn’t mean an incursion by a pandemic or by killer bees. It means a human invasion from a foreign country.Those dictionaries tell us that “invasion” frequently referred to incursions other than military attacks. Thus, Nathan Bailey’s 1783 English dictionary described it as “a descent upon a country, an [sic] usurpation, or encroachment.” (Founding-era dictionaries usually separated alternative definitions by punctuation alone, rather than by numbers.) Bailey defined usurpation as “a taking wrongfully to one’s own use that which belongs to another.” No actual violence was necessary.
“Usurpation” and “encroachment” certainly describe what illegal immigrants are doing at the border.
Here is the entry for the word invasion in Francis Allen’s 1765 dictionary: “the entrance or attack of an enemy on the possessions or dominions of another; an encroachment, or unlawful attack of the rights of another.” The latter two definitions clearly describe what is happening at the border today.
Similarly, in Frederick Barlow’s compilation (1772–1773), to invade meant “to enter into a country in a warlike manner. To attack; to assail or assault. To make the first attack. To seize on like an enemy. To encroach.”
Whether or not swarms of illegal immigrants are actually attacking, assailing, or assaulting, they certainly are encroaching.
However, in 18th-century usage, “hostile” didn’t necessarily imply a military-style attack. It often meant “adverse to” or “without permission.” Johnson, for instance, gave three definitions of hostile: (1) adverse, (2) opposite, and (3) suitable to an enemy. Only the last sounds anything like a military operation. The entry in Ash’s dictionary was similar.
Domestic Violence
The third obligation imposed by the guarantee clause is to protect the states against domestic violence when formally requested to do so. Although illegal immigrants have committed a fair amount of violence, none of the state legislatures has demanded protection under this portion of the guarantee clause. If a state does so, that will trigger another presidential obligation.Are These Obligations Enforceable?
The Supreme Court has held that issues pertaining to the republican form of government are for congressional determination, not for the judiciary. Such cases are nonjusticiable. However, for the other two obligations, the case for court review is much better. If a state sues the federal government for failing to defend it against invasion or domestic violence, then there are two adverse parties—state and federal government—each strongly motivated to present the judges with the information they need to decide the case. This is an important criterion for justiciability.Even if the courts refuse jurisdiction, a state making a formal charge thereby presents its case to the court of public opinion: “We are being invaded. We have asked for help. The president is obligated to provide it but refuses to do so. Hold him accountable.”
All the states on the southern border should make those formal charges. Loud and clear.