Is It Legal for Trump to Use the Army at the Border?

It is absurd to claim that our military cannot defend our borders.  Yet "That is illegal!" shout internationalists who never wanted our U.S. border protected anyway.  Activists proclaim that the U.S. military is crippled under an 1878 law, the Posse Comitatus Act, found at 18 U.S.C. § 1385.  We can do nothing but watch helplessly, they argue, as foreigners flood across the frontiers.

The Posse Comitatus Act of 1878 prohibits the use of the military for law enforcement purposes.  There is actually a lot of scholarly analysis published by legal experts in law review journals.  But most political rhetoric is muddled propaganda.

So is it a 'law enforcement' function to stop invaders from another country from crossing our border?  Is it a military function if citizens of a foreign country approach our border to enter illegally?  Or is that a police function?  

If securing our nation's borders is not a proper military role, then what is?   Are foreign adventures around the world meddling in other countries' affairs (to use the rhetoric of opponents of military power) the only proper role of the military?  What kind of thinking says it is okay to send the military around the other side of the planet, but not to defend our own country's borders at home?

Even as thousands of opportunists are marching from Central America towards the U.S. - Mexican border -- proudly waving the flags of the nations they claim are persecuting them -- President Donald Trump has ordered 5,200 additional troops to block them.  Trump has told tough-as-nails General "Mad Dog" Mattis to keep the invaders out of our country.   (The deployment is called Operation Faithful Patriot.)  If one group of thousands make it across, then – just as happened in Europe -- those thousands will turn into floods of tens of thousands, then hundreds of thousands crossing our frontiers.

New regulations can clarify that protecting the border does not count as "law enforcement."  Secretary of Defense Jim Mattis, Secretary of Homeland Security Kirstjen Nielsen, and Attorney General Jeff Sessions can order "rule making" to explain the meaning of the law.  New regulations should further clarify that the prohibition of the Posse Comitatus Act is limited to law enforcement on domestic U.S. soil.

Agency "rule-making" -- the promulgation of new regulations -- can define parts of a law that are unclear.  Therefore, new regulations can identify what is "law enforcement" and what is not.  This works because the courts are required to give deference to any reasonable interpretation of laws made by the agency entrusted with implementation.  It is assumed that where Congress left definitions or details unclear, it was trusting the experience of the appropriate agency to fill in the details.   This is governed primarily by Chevron U.S.A., Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837 (1984), rehearing denied, 468 U.S. 1227 (1984).

Posse Comitatus is the power of the Sheriff of a county or other official to call upon the "The entire population of a county above the age of fifteen, which a sheriff may summon to his assistance in certain cases; as to aid him in keeping the peace, in pursuing and arresting felons, etc." Black's Law Dictionary Free Online Legal Dictionary 2nd Ed.

In the U.S., after the military was used for civil administration in defeated southern states following the Civil War, concerns about the power of the military being abused came to a boil.  The act says:  "Whoever, except in cases and under circumstances expressly authorized by the Constitution or Act of Congress, willfully uses any part of the Army or the Air Force as a posse comitatus or otherwise to execute the laws shall be fined not more than $10,000 or imprisoned not more than two years, or both."  (The Air Force was added in 1956, but curiously not the Navy.  It has been assumed that when a State's National Guard is called up under the President's authority, the prohibition also applies.  Existing law allows the National Guard to operate either under a State's governor or directly under the president's command.)

What does this mean?  The concept of "a posse comitatus" was that within the borders of a county the proper county authorities (usually the sheriff) could call upon the able-bodied adult population (then male only) to assist the duly-constituted law enforcement officials.  The concept was not that there could be a chain of command separate from county officials.  Furthermore, posse comitatus strongly suggests internal police action within the interior territory of a county.  This does not seem relevant to the international border.

Is it 'executing the law' to block a trespasser at the border?  Well, arguably, perhaps if a military soldier is exercising the discretion whether to allow a foreigner in to the country or not, that might seem too close to what the Border Patrol does.  Arresting people at the border for prosecution sounds like law enforcement.  But the fact that it happens at the border to stop people from unauthorized entry sounds like a military function to defend the country. 

These are difficult lines to draw.  But blocking anyone from crossing the border without any discretionary decision is clearly a military defense of the border.  Telling people to go the nearest official entry gate is a military, not police, function.  Even transporting people due to the risks of exposure in the wilderness to the nearest official border crossing should be defined as military defense of the border (as opposed to just sending people back into the desert). 

When has the Army or Air Force been used "to execute the laws"?  Precedents and scholarly analysis suggest the Posse Comitatus Act is violated (a) when the armed forces perform tasks ordinarily assigned to civil government and not to them, or (b) when the armed forces perform tasks assigned to them solely for purposes of civilian government.  When there is a dominant military purpose, it is believed that an incidental benefit to civilian officials is not prohibited.  However, that interpretation needs to be confirmed.

Intimidation is part of the problem.  If it remains unclear what is permitted, military officials will be afraid to participate in protecting the border.  Furthermore, the DoD seems to have invented a lot of its own rules and traditions that are far more restrictive than what the act actually says.  Issuing new regulations will provoke clear court decisions.  This can take time.  So a prompt beginning is needed.

Also, the regulations should define taking people into custody and sending them back to the Mexican side of the border -- but at a safer venue -- as an exception to being on U.S. soil within the meaning of asylum laws.  The military could shoot people who refuse to go back, or taser them.  But we want use nonviolent procedures instead.

If President Trump proclaims the right to enter Mexican territory to make sure trespassers get back to a safe point inside the wilderness frontier, Mexico's pride would demand that they come and retrieve those people themselves rather than allow U.S. personnel to do it.

Congress should amend the law, but since it is unlikely that they will do so, clarifying the law through regulations is the best that the Trump Administration may be able to do.