Whether you consider everyone should have a right to life , autonomy and the pursuit of happiness , American - elan , or whether you trust Americans should guard their reign with everything they ’ve got — or , perhaps , you consider both ; those aspect may not be mutually exclusive — we all can agree on this : The U.S.-Mexico mete remain aflashpoint in American politics .

There are troops there . A president consecrate to shut the border and defend the country with " lethal force " if necessary . A surge of immigrants need in . Tear throttle , concertina wire , wall … .

This , too , is undeniable : The problem is not going away any time soon .

U.S. troop at Mexican border

The Immigrant Question

A group of immigrant from Central America trying to get into the U.S. — some de jure , some it is suppose by whatever means they can — prompted President Donald Trump in November 2018 to send more than 5,000 troops to the Mexican edge . That , by the way , ismore troops than the U.S. has in war - ravaged Syria .

The presidential order now set up a quite a little of questions , like : Why so many troops for a few thousand unarmed immigrants ? What are these troops doing down there ? What can they do ? Can U.S. troops give notice on foreign civilian ? Can they utilize deadly force ? Should they ?

Amid all the uncertainty , one doubtfulness nag at many observers : Is send federal troops to the border even effectual ? As it turns out , many propose , because of a portion of a 140 - year - former U.S. legal philosophy know colloquially as the Posse Comitatus Act , that it is n’t .

Central American migrant caravan

TheCongressional Research Serviceexplains :

Posse comitatus — Latin for " power of the county , " an idea that allow law of nature enforcement to local authorities , not the feds — only can be take out , the statute allege , " in cases and under context expressly authorized by the Constitution or Act of Congress . "

In this instance , Trump has declared a constitutional exception , underArticle IV , Section IV , which guarantee that the federal governance will protect states from " invasion " and " domesticated violence . "

Whether that ’s valid depends on which side you abide .

" The attorney would call it a grey expanse , " saysWilliam C. Banks , a law professor emeritus at Syracuse University and the co - generator of " soldier on the Home Front : The Domestic Role of the American Military . " " Posse comitatus is n’t the only legal problem . Everything that the United States does has to be establish on some sound authority . It ’s not clear to me what the effectual authorisation is to even direct the military down there . [ Trump ] has n’t say , and no one else has said , other than ' We need them down because we get some tough mass come at us on the mete . ' That ’s not a legal theory .

" In my view , the strongest arguing for him to have the armed services at the boundary line is a strong-arm threat to the United States , which would trigger his Constitutional powers as Commander in Chief . I do n’t sleep with , from what I ’ve see , that the facts justify that . Without that , he has no authority to be there . "

Invasion or Not?

go around the Posse Comitatus Act gets tricky , as the Congressional Research Service points out . If the law is stick to strictly — if the feds keep hands off of local jurisprudence enforcement — an uprising can pass off ( as in the 1786 - 87 Shays Rebellion ) . If , as with Trump ’s soldiery , the feds jump-start into an already volatile state of affairs , they could worsen it , and a Kent State - eccentric catastrophe could occur ( though that involved the Ohio National Guard , not federal troops ) .

Many , include Banks , believe that Trump sent the troop to the perimeter as a political ploy , a way of stoking his Republican electoral base before themidterm election . But even if that is n’t the case , even if the president truly believed an " encroachment " of immigrants was close at hand and that it was a threat to the U.S. , 5,000 - plus troops seems , at least so far , a bit much .

States already had deployed National Guard troops to the mete when the administration sent in the Union military personnel . The U.S. Customs and Border Protection ( CBP ) is there . They are all coordinating with Mexican authorities . Despite a clash on Nov. 25 , 2018 , that involvedtear gas(released by the CBP , not the feds ) and rock ‘n’ roll - throwing immigrant stress to transgress the border , it does n’t appear that the U.S. military is needed . So far , federal troops have been relegated toproviding supportto the CBP ( DoT , stringing concertina telegram , building barriers ) . Most U.S. troop are n’t even carrying weapon system .

" The [ administration ’s ] order allow them to potentially do some things that would cause a lot of us to get nervous , " Banks says . " But [ U.S. Secretary of Defense James ] Mattis said the other day , ' Look , they are n’t convey their weapons flop now . I do n’t retrieve they ’ll have to . ' "

If that meter ever comes , then thousands of troops may be called for . Until then , though , local police force enforcement seems to have this handled .

" If there ’s a real scourge to the perimeter , yes , [ the president ] has constitutional authority to act . And then he can sort of loose the military personnel , " Banks says . " It ’s just surd to envisage that happening . "