It has been reported that there was a robust WH debate over the scope of empowering the US Military to assist in border protection, as the issue of posse comitatus was being discussed:

The White House late Tuesday signed a memo allowing troops stationed at the border to engage in some law enforcement roles and use lethal force, if necessary — a move that legal experts have cautioned may run afoul of the Posse Comitatus Act.

President Trump has proven to be very respectful of his constitutional role as commander in chief to protect all Americans. So when he orders US military to help secure our safety and security in supporting and assisting civilian law enforcement  he is well within his constitutional rights. There are several historical examples of the teaming of law enforcement and the military.

Perhaps two very specific examples of the legal consideration of posse comitatus as our troops engage to protect the southern border will show any  “legal experts” that  the military has “been there and done that,” with honor and success.

Navy Ship CO’s comment to the crew of a fast mover drug smuggler:

After flying actual combat scrambles from Key West in the seventies our Squadron would often go back to train in flying areas off Key West. During that time USN Pegasus Class hydrofoils began being employed to chase down fasts moving "skunks," navy designation of unknown surface contacts.

 Hydrofoils had a top end of 48 kits (55 mph)so that they were very capable ships for the drug interdiction mission. These naval engagements were during the famous "Save the Bales" drug wars originating in the Caribbean.  An infamous Tee shirt showing floating marijuana bales with that message and was all the vogue as high speed boats made drug runs up the Keys to deliver their products

They key to success was having a Coast Guard Law enforcement detachment on board. US Naval ships with a member of the US Coast Guard were then legally allowed to board, inspect and arrest criminal crews. And with an armament of a 75 mike mike cannon woe be to the drug smugglers that wanted a running at sea gun battle with a Pegasus.

Coast Guard Seamen Chris Bedford, Daniel Rowland, Stephen Hartie and Daniel Rowland (left to right) help load one of 37 bales of cocaine the crew of U.S. Coast Guard Cutter Mohawk seized on a drug interdiction patrol. Coast Guard photo  

A little-known but brilliant chapter in Navy history was perfectly captured in the Decommissioning message saluting the Pegasus Class hydrofoils;

From the CNO on 2 July 1993 (R1219102 Jul 93):

Over the last ten years they have set an admirable record in counter drug operations… representing 3 percent of the surface Navy they accounted for 28 % of all Surface Navy-assisted drug seizures.

You have given these proud ships a special place of honor in our Navy’s history.

With reported drug smugglers, known criminals and unknown possible terrorists intermixed with the central immigrant cohorts, if Blackhawks and HUMVEES are planned to be used as a show of force deterrence mission on US side of border, if one ICE agent or other civilian LE official is on board then the mission falls well within the legal boundaries of Possie Comitatus

Death From Above-a Marine Pilot flies to the sound of the guns

Marine helicopter pilot Charles H. "Chuck" Pitman watched the television in horror on Jan. 7, 1973, as authorities tried to stop a sniper or snipers who had invaded the Downtown Howard Johnson's Motor Lodge that morning and fatally shot seven people, including three police officers. Shots rang out from various spots in the 17-story hotel, making police think there was more than one gunman, but the cops eventually contained the killer or killers to the roof.

Chuck Pitman is one of the most legendary Marine Corps pilots in our illustrious history and he was commanding a Marine Helicopter Squadron of Ch-46 Helos flying out of NAS Belle Chasse just up the river from New Orleans:

During his nearly four decades in the Marines, he earned numerous honors, among them a Silver Star for valor, four Distinguished Flying Crosses, a Bronze Star with Combat "V," a Purple Heart and 65 air medals. Nonetheless, he says he is perhaps most proud of having served alongside the New Orleans police during their clash with Essex on one of the darkest days in the city's history, for which he was made an honorary NOPD captain on Nov. 8, 1991.

Believing in the military saying when that lives are being lost it easier to beg forgiveness than ask permission he entered the fight. Seeing American being killed by a cowardly, but sadly effective sniper, then LtCol Pitman flew his CH-46 flew to the sounds of the guns and into harm’s way:

So when Pitman flew his helicopter to the hotel with his crew, he exposed himself to a court-martial: He had deployed military personnel and resources to quell a civil matter, and he did not have permission to do so before taking off.

However, a posse comitatus partnership had been immediately formed:

Pitman agreed to fly a group of well-armed officers … over the hotel to better see where the sniper was hiding. They would try to force the sniper out of his lair.

The cops aboard the Sea Knight ran out of ammunition a couple of times, and Pitman had to land so they could reload. After one of those pit stops, the sniper hit the Sea Knight with gunfire but vanished when the helicopter began to pass over the hotel.”

“When he fired ... at me, the helicopter jumped," Pitman joked, explaining that he instinctively jerked back on his controls. The bullet struck a little bit above the cockpit, hitting the transmission casing.

Pitman steadied the helicopter and kept the searchlight on the sniper. Saacks, his colleagues in the helicopter and the officers in surrounding buildings emptied their weapons at the figure on the roof. The sniper collapsed and died. He was struck more than 200 times.

Now here is where the story takes a very positive turn in recognizing the Military/Civilian partnership during a very dangerous time:

 Pitman soon learned that his actions could lead to a court-martial. But he said the issue was dropped after his commander sought out longtime U.S. Rep. F. Edward Hebert, a New Orleans Democrat and at the time the powerful chairman of the House Armed Services Committee.

US Democrat representative F. Edward “Eddie” Hebert was a famous pro-military towering figure of the last century. He fully supported then LtCol Pitman’s actions.  Lt-Gen Chuck Pitman USMC, now retired, went on to serve as our most senior Marine Aviator. On that day in New Orleans a new chapter of constitutionally protected posse comatitus history was successfully written.

Would there be room today in the new Democrat Controlled Congress for a Chairman Hebert?