As thousands of migrants in a caravan of Central American asylum-seekers converge on the doorstep of the United States, what they won’t find are armed American soldiers standing guard.

…That’s because U.S. military troops are prohibited from carrying out law enforcement duties. [emphasis: mine]

…That means there will be no visible show of armed troops, said Army Maj. Scott McCullough, adding that the mission is to provide support to Customs and Border Protection. 

Migrants won’t see armed US soldiers on border – ABC News

Not a huge  compliment to the Customs and border Patrol folks that the Cheeto doesn’t think they are capable of defending themselves from exhausted and perhaps starving and dehydrated migrants.