Congress can veto override a bill to close the border. So corrupt (imo) Congress can share responsibility for an invasion if lawmakers continue to sit on their hands.
In the meanwhile, the states expressly constitutionally gave themselves the power to fight an invasion without having to wait for the corrupt federal government to help (my wording).
"Article I, Section 10, Clause 3: 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 [emphases added]."
So desperate Democratic border state governors can take full blame for initial invasion imo.
As a side note to this post, North Mexico (California) citizens are reminded that they will eventually not be able to use "evil" natural gas to keep themselves warm in winter and that they will instead have to take turns with illegal immigrants with respect to using electric heaters imo. /semi-sarc
Also, let immigrants in drought-ridden North Mexico use the fresh water that the state drains into the ocean every year. /semi-sarc
Yes, tens of thousands of foreigners illegally crossing our border is an invasion by any definition. What are the chances that Katie Hobbs will do anything at all to defend Arizona, ever?
And Article IV, Section 4:
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.