On January 20, 2025, President Trump issued a proclamation entitled Guaranteeing the States Protection Against Invasion. This Proclamation is more limited than the Trump administration may care to admit. This article explores some of those limitations.

The Constitution, Article I, Section 8, Clause 4, gives Congress exclusive power over immigration

Article I, Section 8, Clause 4, of the Constitution reads: Congress shall have the power to establish a uniform rule of naturalization. It is settled law that this clause assigns to Congress exclusive power over immigration and the status of aliens. Under the Constitution, the President has no authority in the realm of immigration and naturalization.

Presidential authority under the INA is limited to only the suspension of and restriction upon alien entry into the country

Congress delegated very limited authority to the President to suspend and restrict entry of aliens into the United States. The Immigration and Nationality Act (INA) is a sprawling chunk of statutes dictating immigration and pathways to citizenship, lawful presence, and refugee status, among other matters.

The limited delegation at INA section 212(f), 8 U.S.C. 1182(f), reads:

(f) Suspension of entry or imposition of restrictions by President

Whenever the President finds that the entry of any aliens or of any class of aliens into the United States would be detrimental to the interests of the United States, he may by proclamation, and for such period as he shall deem necessary, suspend the entry of all aliens or any class of aliens as immigrants or nonimmigrants, or impose on the entry of aliens any restrictions he may deem appropriate.

The President is authorized to:

• Suspend entry of aliens and
• Impose restrictions on the entry of aliens.

Under the INA as it currently exists, the word “entry” is not defined. An earlier version of the law defined “entry” to mean “any coming of an alien [without lawful permanent residence] into the United States”. The 1996 amendments removed “entry” as a defined word and added a definition for “admission”. A reason for this change was to restrict certain immigration proceedings from those who unlawfully enter the country.

Admission means “the lawful entry of an alien into the United States after inspection and authorization by an immigration officer.” 8 U.S.C. 1101(13).

Throughout the INA, Congress intentionally uses entry when it means entry and admission when it means admission. The delegating provision in the INA uses the word entry, as does the Proclamation. It was not the intent, or at least the effect, of Congress to give the President authority to suspend or restrict anything other than entry.

The Proclamation is limited to only people who entered or would enter the country on or after January 20, 2025.

The guarantee clause in the Constitution at Article IV, Section 4, was written in the context of States fearing other States

The Trump Proclamation invokes the guarantee clause at Article IV, Clause 4, of the Constitution:

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.

Reading this section in isolation, you might reasonably think “invasion” means foreign invasion. The Proclamation relies on such an isolated reading when it argues that the guarantee clause requires each branch of the federal government to protect States from foreign invasion.

However, the law is read in context. Article IV deals entirely with States and their relationships with other States. When the Constitution was written, the Union was new and States were uncertain they could trust each other. The matter of interstate invasions and security was discussed at the Constitutional Convention, where this section was rewritten to its final form, and in Federalist No. 21 (Hamilton) and No. 43 (Madison).

Reading the sentence in the context of Article IV, the guarantee clause most likely was intended to protect a State from invasion by another State. In this context, the guarantee clause cannot be fairly applied to immigration.

Whether immigration constitutes an invasion is a political question that Courts Won’t Decide

Even if Article IV, Section 4, meant the federal government must protect States against foreign invasion, questions remain: can immigration constitute an invasion and if so, under what circumstances. In the last many years, multiple States have argued that illegal immigration constitutes invasion and the federal government should act. At least two federal courts ruled that immigration cannot constitute invasion.*

Whether immigration can constitute an invasion may be considered non-justiciable or a political question. Courts settle questions of law and questions of fact. A political question is one specifically determined by the Constitution or not considered at all by the Constitution.

Whether immigration can constitute an invasion is not at all considered by the Constitution. However, the Constitution specifically and exclusively authorizes Congress to deal with invasions. Courts have considered some cases related to Article IV, Clause 4, non-justiciable.**

The Constitution, Article I, Section 8, Clause 15, and Section 10, Clause 3, indicate Congress’ exclusive power to repel invasions

The President and Congress have distinct roles related to foreign affairs. Under Article II, Section 2, Clause 2, of the Constitution, the President has the power to make treaties and appoint ambassadors, but even that power is limited by the advice and consent of the Senate.

Congress has exclusive power to repel invasions.

Article I, Section 8, Clause 15, reads: The Congress shall have power to provide for calling forth the militia to execute the laws of the Union, to suppress insurrections and repel invasions.

Article I, Section 10, Clause 3, reads: No State shall, without the consent of Congress, lay any duty of tonnage, keep troops, or ships of war in time of peace, enter into any agreement or compact with another State, or with a foreign power, or engage in war, unless actually invaded, or in such imminent danger as will not admit of delay.

Congress’ exclusive power to repel invasions makes Congress the appropriate decider of whether and under what circumstances immigration can constitute invasion.

The language in the Trump Proclamation requires definition

Limitations on the President’s authority make clear terms essential to the Proclamation. Throughout the Proclamation, a term is used to describe which aliens are subject to suspended or restricted entry: “aliens engaged in the invasion across the southern border.” In two additional instances, this group is “aliens involved in the invasion across the southern border.”

By its own wording, we see that the Proclamation doesn’t apply to:

• Aliens entering at the eastern, western, or northern borders;
• Aliens entering at the southern border but not engaged in the invasion thereof.

Clarification is needed to understand:

• What does “engaged in the invasion” mean?
• How do we know whether an alien is “engaged in the invasion”?
• Who decides whether an alien is “engaged in the invasion”?

Section 1. Suspension of Entry

The Proclamation relies on the President’s authority delegated by the INA to suspend entry of “aliens engaged in the invasion across the southern border” until he finds that the invasion has ceased.

This language closely follows the INA section 212(f), 8 U.S.C. 1182(f). However, the term “aliens engaged in the invasion across the southern border” is not well defined. Since the Proclamation does not suspend entry of all aliens at the southern border, there there must be aliens engaged in invasion and aliens not engaged in invasion. Who has the ability and authority to tell them apart?

Section 2. Imposition of Restriction on Entry

The Proclamation relies on the President’s limited authority delegated by the INA to restrict “aliens engaged in the invasion across the southern border” from using INA processes to stay in the U.S. until he finds the invasion has ceased.

This language follows the INA, 8 U.S.C. 1182(f). However, the problem of identifying “aliens engaged in the invasion across the southern border” recurs.

Section 3. Suspension of and Restriction on Entry for Aliens Posing Public Health, Safety, or National Security Risks

This section identifies a second category of aliens subject to the Proclamation. The second category is better defined: aliens who fail to provide officials with sufficient medical and criminal background information to determine their admissibility before entering the country.

Having a second category underscores that not all aliens are “aliens engaged in the invasion across the southern border.”

Here, another limitation becomes more apparent. The President is not suspending admission of an alien but only their entry. Otherwise, this section 3 would be an unnecessary repetition of the first two sections.

Section 4. Constitutional Suspension of Physical Entry

Based on the President’s Article II authority over foreign affairs and the guarantee clause of Article IV, the Proclamation suspends “physical entry of any alien engaged in the invasion across the southern border.”

Under the INA, entry is physical entry. Entry is not admission. Entry is not continued presence. So this section either repeats the first two sections or is the only enforceable section (if “entry” was intended to mean something other than physical entry in the other sections).

Section 5. Operational Actions to Repel the Invasion

“The Secretary of Homeland Security…shall take all appropriate action to repel, repatriate, or remove any alien engaged in the invasion across the southern border of the United States on or after the date of this order…”

• Any alien who entered before that date or
• Any alien not engaged in the invasion across the southern border, regardless of their date of entry.

This is a much more limited directive than it may appear. The President has no authority to repel invasions. The President has no authority to repatriate or remove aliens. The President has only the authority to suspend and restrict the entry of aliens.

Any action under this directive must lawfully be limited to those “aliens engaged in the invasion across the southern border” entering the country on or after January 20, 2025. The directive does not lawfully extend to:

• Aliens who entered the country before January 20, 2025, or
• Aliens not engaged in invasion.

How Concerned Should I Be?

If the limitations of the Proclamation are understood, the Proclamation is not scary. The problem is that the limitations may not be well understood. Even if all the limitations are well understood and everyone agrees on them, the Proclamation fails to give officials and aliens clarity about who is affected. There’s real concern that the Proclamation or the actions that flow from it constitute intended or accidental Presidential overreach. These concerns lean into fear and uncertainty in the country and around the globe.

This Proclamation should mean nothing to anyone who entered the country before January 20, 2025. It shouldn’t mean much for most aliens at the southern border. The only people who should need to be concerned are “aliens engaged in the invasion across the southern border”, whoever they are.

*These federal cases ruled that immigration cannot constitute an invasion:

• Padavan v. United States, 82 F.3d 23 (1996)
• New Jersey v. U.S. 91 F.3d 463 (1996)

**These federal cases ruled that question related to Article IV, Clause 4 are non-justiciable:

• Luther v. Borden, 48 U.S. 1 (1849)
• Colegrove v. Green, 328 U.S. 549 (1946)

Note: This article does not undertake a full discussion of caselaw related to immigration, invasion, or Article IV.