Conservative groups are calling on states at the southern border to take matters into their own hands to combat the continuing migrant crisis amid discussions about whether the surge can be classified as an "invasion."

"What is happening at the southern border is without precedent in American history. President Biden has abandoned his core responsibility to ensure the integrity of our nation’s borders," the Federation for American Immigration Reform (FAIR) said in a statement Friday. 

"Not only is illegal immigration at a record high, the magnitude of death and destruction experienced in the United States at the hands of ruthless and powerful cartels is well documented. The Biden administration has created a constitutional challenge leaving states to explore alternative solutions."

ARIZONA AG BRNOVICH ISSUES LEGAL OPINION DECLARING BORDER CRISIS ‘INVASION’ UNDER CONSTITUTION 

The crisis at the southern border, which saw more than 10,000 lbs of fentanyl seized and more than 1.7 million migrant encounters in FY 2021, has prompted Republican states to take matters into their own hands, including deployment of law enforcement to tackle illegal immigration in states like Texas and Arizona. But some conservatives have been arguing that the crisis constitutes an "invasion," which they argue has potential legal implications.

Ken Cuccinelli, acting director of U.S. Citizenship and Immigration Services, speaks during a Bloomberg Television interview in Washington, D.C., Aug. 9, 2019.

Ken Cuccinelli, acting director of U.S. Citizenship and Immigration Services, speaks during a Bloomberg Television interview in Washington, D.C., Aug. 9, 2019. (Andrew Harrer/Bloomberg via Getty Images)

Former acting deputy DHS Secretary Ken Cuccinelli, now at the Center for Renewing America, issued a policy brief in October outlining the legal basis for declaring the crisis an invasion. He argued that the Biden administration has neglected its duties under Article IV, Section 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 from Invasion; and on Application of the Legislature, or of the Executive (when the Legislature cannot be convened) against domestic violence," the article states. 

Consequently, Cuccinelli argued, states could use what he called a "self-help" remedy under Article I, Section 10, Clause 3.

That clause states, "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 delay."

"There can be no disputing that the influx of well over 1.3 million illegal immigrants this calendar year alone and thousands of pounds of fentanyl and other deadly narcotics, facilitated by the widespread human trafficking efforts of violent international drug cartels, constitutes an invasion of the southern border of the United States," Cuccinelli said.

He argues that the declaration then allows for the use of war powers by the governors, including the deployment of the National Guard and Department of Public Safety (DPS) to the border to detain and return illegal immigrants and defend their states against cartels and other criminal groups funneling narcotics into the U.S.

Cuccinelli also argues that citizens could be deputized to help make trespassing arrests and that governors can issue an executive order to task DPS and National Guard units to use school buses to transport illegal immigrants out of the states. He also warned that states should gear up for a legal fight with the Biden administration.

His arguments have picked up steam. Earlier this month, Arizona Attorney General Mark Brnovich issued a legal opinion declaring the situation at the border an "invasion."

"The violence and lawlessness at the border caused by transnational cartels and gangs satisfies the definition of an ‘invasion’ under the U.S. Constitution, and Arizona therefore has the power to defend itself from this invasion under the governor’s authority as commander in chief," Brnovich says. "An actual invasion permits the state to engage in defensive actions within its own territory at or near its border." 

Cuccinelli told Fox News Digital that it was a "big deal" for Brnovich to come to the conclusion he did, saying it was "confirmation that [governors] have legal authority to take matters into their own hands and solve the problem, not just complain about it."

CBP SEES ‘SUBSTANTIAL INCREASE’ IN FENTANYL SEIZURES, CONFIRMS 153,941 MIGRANT ENCOUNTERS IN JANUARY

Since then, both FAIR and the Heritage Foundation issued statements in support of states taking greater action. At Heritage, former acting Customs and Border Protection Commissioner Mark Morgan, along with Heritage experts Mike Howell, Lora Ries and Hans von Spakovsky issued a statement that described governors as the "last – indeed, only – line of defense against the current administration's open-border policies."

They did not comment directly on Brnovich’s declaration, calling it a "novel and untested legal theory" but said they "certainly align with his frustration and the desperate situation that these states, and all of the interior states, are currently facing."

Arizona Attorney General Mark Brnovich

Mark Brnovich on Fox News. (Fox News)

They called for states to use "all lawful tools" to end the crisis and to mount a challenge to a 2012 Supreme Court ruling in Arizona v. United States that found that Arizona’s efforts to crack down on illegal immigration were unconstitutional as they encroached on federal responsibilities. 

"We encourage all states to utilize every legal means at their disposal to address this catastrophic crisis along our southern border," they wrote. "The urgency of the moment requires this. The United States of America simply cannot withstand this attack on our sovereignty endorsed and facilitated from the White House." 

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FAIR, meanwhile, said that Brnovich’s opinion "raises important constitutional questions about what powers states may invoke to defend themselves in the face of the Biden administration’s dereliction of its duty to secure our borders and protect the well-being of its citizens."  

"Our Constitution does not leave states defenseless when the federal government permits a cartel-led invasion that allows criminals to prey upon our nation," the group, which calls for lower levels of immigration overall, says. "We hope that states continue to explore every possible measure to defend themselves. The urgency of the moment requires this. The federal government under President Biden’s leadership got us into this situation, it may very well be the states who help get us out of it."