What our president must do to seal the border.

A migrant caravan from Central America is currently heading en masse to the United States. Its members, several thousand strong, are intent on pouring into the U.S. in what amounts to an invasion force. President Trump has correctly branded the caravan an “onslaught” and an “assault on our country.” The president has promised to use military troops if necessary to close the southern border with Mexico. He also threatened to cut off all foreign aid to those Central American countries that are not doing enough to stop the migration caravan in its tracks.

Members of the caravan have already demonstrated their violent streak during an early stage of their trek, as they approached Mexico. They “forced their way through Guatemala’s northwestern border and flooded onto a bridge leading to Mexico,” AFP reported. These migrants, mainly from Honduras, engaged in violent clashes with Mexican riot police as they tried to surge through police lines and cross the bridge into Mexico. Four Mexican police officers were reportedly injured. “Violent entry into the country not only threatens our sovereignty, but also puts the migrants themselves at risk,” Mexico’s President Pena Nieto said. “Mexico does not permit and will not permit entry into its territory in an irregular fashion, much less in a violent fashion.”

Mexican government officials have said that Mexico would be willing to consider asylum requests from members of the caravan on an individual basis, with the assistance of the United Nations Office of the High Commissioner on Refugees (“UNHCR”). Mexico is proposing that UNCHR establish shelters along Mexico’s southern border with Central American countries. Individuals deemed by the UN agency to be eligible for asylum protection, presumably after performing its standard vetting, would be eligible for placement in a host country willing to accept them, which could be Mexico or the United States. Those deemed not to have a legitimate claim would be sent back to their home countries. If someone manages to slip through this system and travels through Mexico before crossing the Mexico-U.S. border into the United States, Mexico has indicated that it would be willing to accept the return of that individual if the U.S. so wishes. Secretary of State Mike Pompeo said that the United States welcomed and would cooperate with Mexico’s initiative to have Central American migrants processed for possible asylum in Mexico first with UN assistance. The initiative conforms with international law on the handling of claims for refugee status and is an orderly and humane solution to the migration crisis that the caravan has precipitated.

However, the migrant invaders are impatient. “We are going to the United States,” said one of the migrants. “Nobody is going to stop us.” The Associated Press has reported that despite Mexico’s attempt to intervene, “a growing throng of Central American migrants resumed their advance toward the U.S. border early Sunday in southern Mexico.” Their numbers have reportedly grown, after migrants in the caravan decided not to submit to Mexico’s asylum process that would have enabled them to enter Mexico legally. Instead, they took the law into their own hands. Mexico now appears to have largely given up and is doing little to stop them.

The caravan migrants believe that they are entitled to simply pass through Mexico without any interference and ensconce themselves in the United States. A press release issued by the organizers of a similar migrant caravan earlier this year stated a “demand of Mexico and the United States” that “they open the borders to us because we are as much citizens as the people of the countries where we are and/or travel.” This “open borders” demand is a direct challenge to U.S. national sovereignty. Migrants are not entitled to insist upon a “right” to choose the United States as their destination country, including would-be asylum-seekers if they are offered the chance for asylum in Mexico first.

Some of the caravan migrants cry poverty and use children as shields while pleading their case. Others in the caravan have likely learned - from the migrants who preceded them and from open borders advocates encouraging their migration - the playbook of how to exploit the loophole-ridden U.S. immigration laws. They know that their sheer numbers will further overwhelm an already overstretched adjudicative process with many more amnesty claims. Once in this country, the migrants, especially those with children in tow, are likely to be released into the community-at-large, pending the outcome of their asylum hearings, which could take place years later. They may well skip their hearings altogether, as many before them have done, and remain free to live in our country at American taxpayers’ expense indefinitely. Other migrants in the caravan who manage to make it to the U.S. border will simply enter illegally at unguarded points without even the pretense of seeking asylum unless they can be stopped first. Terrorists and criminal gang members are free to take part in the caravan with little chance of detection.

President Trump has vowed to use the military to seal the southern border of the United States with Mexico, if necessary – a stretch of territory as long as 2000 miles. Aside from logistical issues, questions have been raised as to whether the president has the legal authority to take such action in enforcing U.S. immigration laws, at least with respect to utilizing active-duty members of the army, navy, air force and marines. Those who claim that the president does not have such authority cite the Posse Comitatus Act of 1878, as amended from time to time, which prohibits active duty military troops from executing the country’s laws unless expressly authorized by the Constitution or an Act of Congress. This statute does not apply to the National Guard operating under state authority.

A federal court has held that the Posse Comitatus Act “makes unlawful the use of federal military troops in an active role of direct law enforcement by civil law enforcement officers,” which includes “arrest; seizure of evidence; search of a person; search of a building; investigation of crime; interviewing witnesses; pursuit of an escaped civilian prisoner; search of an area for a suspect or other like activities.” Military personnel can do little more than maintain border fences and vehicles and perhaps also assist with surveillance, including in connection with drugs smuggling, if the Posse Comitatus Act is interpreted as restrictively as open borders proponents are likely to advocate in court.

However, repelling an organized force of unvetted migrants, who may include terrorists and foreign criminal gang members, from entering this country in the first place is not simply civil domestic law enforcement. It is a military response to a genuine threat to U.S. territorial sovereignty and national security originating from foreign territories. The military response would be directed by the president of the United States who is vested with the constitutional authority of commander in chief. The president would be using the military to implement the constitutional mandate of Article IV, Section 4 of the Constitution that the “United States shall guarantee to every State in this Union a Republican Form of Government, and shall protect each of them against Invasion.”

Moreover, the Posse Comitatus Act was intended to protect Americans within the boundaries of the United States from military rule. Its original purpose was to put an end to the use of federal troops to police state elections in the ex-Confederate states where the civil power had been reestablished. As one federal court stated, the Posse Comitatus Act is “the type of criminal statute which is properly presumed to have no extraterritorial application in the absence of statutory language indicating a contrary intent.” There is nothing in either the legislative history or text of the Posse Comitatus Act.to indicate that its drafters intended to prohibit the president’s use of military troops to block aliens gathered together in a horde from attempting to cross into our country after having violently clashed with the police of another country en route and having willfully evaded that country’s laws. Terrorists may well be concealing themselves in the migrant caravan. Hezbollah, for example, has already managed to penetrate the U.S. border with Mexico, posing a serious national security threat.

The Supreme Court recently upheld the constitutionality of President Trump’s executive order limiting the entry of aliens from certain countries on national security grounds, pending a thorough review of the vetting process. The Court relied on §1182(f) of the Immigration and Nationality Act, which enables the President to “suspend the entry of all aliens or any class of aliens” whenever he “finds” that their entry “would be detrimental to the interests of the United States.”

Analogously, if the president determines that it is necessary to use active members of the military to enforce federal authority in situations he deems potentially dangerous to national security, there is a statutory exception to the Posse Comitatus Act which should allow him to do just that (10 U.S.C. § 332, renumbered §252). This provision states that the president may “use such of the armed forces, as he considers necessary,” to enforce “the laws of the United States” whenever he “considers that unlawful obstructions, combinations, or assemblages” make it “impracticable” to enforce such laws “by the ordinary course of judicial proceedings.” The migrant caravan aimed at entering the United States is an “assemblage” by definition. This assemblage has already acted unlawfully in violent clashes with Mexican riot police, after which some members then entered Mexico illegally despite being given the chance to submit to a legal process for asylum claims. U.S. border enforcement officials have already been overwhelmed by the number of illegal aliens and would-be asylum seekers from Central America. The current migration caravan will further burden the adjudicative system for amnesty hearings to the point of implosion.

President Trump tweeted on Sunday: “Full efforts are being made to stop the onslaught of illegal aliens from crossing our Southern Border. People have to apply for asylum in Mexico first, and if they fail to do that, the U.S. will turn them away.” If he needs the military to protect the border from the migrant caravan invasion, so be it.