The U.S. Constitution says that states have the right to protect themselves from an invasion.
“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,” Article IV, Section 4 of the Constitution states.
In addition to Article IV, Section 4, another clause of the Constitution grants states the ability to declare war against an “invasion.”
The group worked with the Center for Renewing America, a conservative organization led by former Trump administration officials, to make the declaration.
“For the first time in U.S. history, several counties in Texas, outside of Congress, have declared an invasion–a Constitutional solution we have been advocating for over a year,” former Trump administration officials Russ Vought and Ken Cuccinelli, both affiliated with the Center for Renewing America, said in a joint statement Monday.
https://www.dailycaller.com/2022/07/05/border-abbott-texas-migrants