US veterans decried Donald Trump’s orders to restore an accused war criminal's rank in the Navy, saying the decision “sets a dangerous precedent” and suggests the commander-in-chief views the military “as a tool for massacres”.

Numerous veterans spoke out about the move to The Independent after Secretary of Defence Mark Esper confirmed he was ordered by the president to retain Navy SEAL Eddie Gallagher’s status in the elite service, as well as his Trident pin, a prestigious special warfare insignia.

“Ever since Donald Trump became president he’s been tearing the military apart, putting troops in the difficult position of needing to choose between obedience to his unhinged orders, and staying true to our code of honour,” said Alexander McCoy, a former Marine and political director of the veteran group Common Defence. “By pardoning war criminals because Fox News told him to, Trump showed he sees our military as a tool for massacres, not as the professional, honourable force we aspire to be.”

Gallagher, who was accused of killing Iraqi civilians and an unarmed Islamic State fighter, was acquitted in July of murder but found guilty of posing in a photograph with a war casualty. Mr Trump later intervened in the case, restoring Gallagher’s rank to E-7, otherwise known as a chief petty officer, and demanding he be allowed to keep his Trident and retire at the rank and pay grade he earned before the allegations were brought against him.

The defence secretary announced on Monday that Gallagher “will retain his Trident as the Commander in Chief directed and will retire at the end of this month”, adding that the case “has dragged on for months” and “must end”.

US Navy SEAL on trial accused of murdering wounded Isis fighter Show all 11 1 /11 US Navy SEAL on trial accused of murdering wounded Isis fighter US Navy SEAL on trial accused of murdering wounded Isis fighter US Navy SEAL Special Operations Chief Edward Gallagher leaves court with his wife Andrea 17 June 2019. He is on military trial at San Diego Naval Based accused of murdering a wounded Isis fighter in Iraq in 2017. REUTERS/Mike Blake US Navy SEAL on trial accused of murdering wounded Isis fighter US Navy SEAL Special Operations Chief Edward Gallagher leaves court with his wife Andrea 18 June 2019. REUTERS/Mike Blake US Navy SEAL on trial accused of murdering wounded Isis fighter U.S. Navy SEAL Special Operations Chief Edward Gallagher, charged with war crimes in Iraq, is shown in this undated photo provided May 24, 2019. Courtesy Andrea Gallagher/Handout via REUTERS ATTENTION EDITORS - THIS IMAGE WAS PROVIDED BY A THIRD PARTY. NO RESALES, NO ARCHIVE HANDOUT Andrea Gallagher via REUTERS US Navy SEAL on trial accused of murdering wounded Isis fighter US Navy SEAL Special Operations Chief Edward Gallagher poses with his wife Andrea. Andrea Gallagher via REUTERS US Navy SEAL on trial accused of murdering wounded Isis fighter U.S. Navy SEAL Special Operations Chief Edward Gallagher, charged with war crimes in Iraq, is shown in this undated photo provided May 24, 2019. Courtesy Andrea Gallagher/Handout via REUTERS ATTENTION EDITORS - THIS IMAGE WAS PROVIDED BY A THIRD PARTY. NO RESALES, NO ARCHIVE HANDOUT Andrea Gallagher via REUTERS US Navy SEAL on trial accused of murdering wounded Isis fighter This undated selfie provided by Andrea Gallagher shows her husband, U.S. Navy SEAL Edward Gallagher, who has been charged with allegedly killing an Islamic State prisoner in his care and attempted murder for the shootings of two Iraq civilians in 2017. Gallagher is scheduled to go on trial Monday, June 17, 2019. (Edward Gallagher/Courtesy of Andrea Gallagher via AP, File) Edward Gallagher Andrea Gallagher via AP US Navy SEAL on trial accused of murdering wounded Isis fighter Former US Army member King Cohn arrives at court to support US Navy SEAL Special Operations Chief Edward Gallagher during the first day of jury selection on 17 June 2019. REUTERS/Mike Blake US Navy SEAL on trial accused of murdering wounded Isis fighter Former U.S. army member King Cohn arrives at court to support U.S. Navy SEAL Special Operations Chief Edward Gallagher during the first day of jury selection at the court-martial trial at Naval Base San Diego in San Diego, California , U.S., June 17, 2019. REUTERS/Mike Blake MIKE BLAKE REUTERS/Mike Blake US Navy SEAL on trial accused of murdering wounded Isis fighter FILE PHOTO: U.S. Navy SEAL Special Operations Chief Edward Gallagher, charged with war crimes in Iraq, is shown in this undated photo provided May 24, 2019. Courtesy Andrea Gallagher/Handout via REUTERS ATTENTION EDITORS - THIS IMAGE WAS PROVIDED BY A THIRD PARTY. NO RESALES, NO ARCHIVE/File Photo Handout . Andrea Gallagher via REUTERS US Navy SEAL on trial accused of murdering wounded Isis fighter Defence attorney Timothy Parlatore, representing US Navy SEAL Special Operations Chief Edward Gallagher, speaks with reporters at a pre-trial hearing. Earnie Grafton/REUTERS US Navy SEAL on trial accused of murdering wounded Isis fighter FILE - This 2018 file photo provided by Andrea Gallagher shows her husband, Navy SEAL Edward Gallagher, who has been charged with murder in the 2017 death of an Iraqi war prisoner. Lawyers for Gallagher are seeking to have the charges dismissed for alleged prosecutorial misconduct. Attorneys for Special Operations Chief Gallagher are scheduled to argue in military court Wednesday, May 29, 2019, that the case against him has been tainted by lies, withholding evidence and conducting surveillance on the defense. (Andrea Gallagher via AP, File) Andrea Gallagher Andrea Gallagher via AP

The announcement followed Mr Esper's firing of Navy Secretary Richard Spencer just two days earlier. CNN reported the defence secretary learned during the weekend that Mr Spencer had worked on a “secret agreement with the White House” involving Gallagher's dismissal from the Navy.

In his statement, Mr Esper said the firing was not about Gallagher, but rather “Secretary Spencer and the chain of command”.

The president’s demands could cause “significant long-term damage to the Naval Special Warfare community,” according to James Waters, a former Navy SEAL platoon commander and White House staff member in the Bush administration, who told The Independent: “The only people who weigh in on whether a Navy SEAL deserves to keep his Trident are people who have their Trident.”

“Every SEAL knows he must ‘earn your Trident every day’ – even after officially qualifying – and the same standard should apply here,” Mr Waters said. “Unless you’ve been through Basic Underwater Demolition/SEAL training and served in the Teams and know the specific facts related to a person’s performance, you’re not qualified to weigh in.”

He added: “This is vital to maintaining the high standards required to be effective in the Teams and on the battlefield. The absolute last thing the nation needs is to open the floodgates to outside interests determining who gets to wear and keep the Trident.”

Gallagher has regularly appeared on Fox News following his court martial, which was the result of his fellow SEALs reporting him for allegedly killing a captured teenage ISIS fighter with a hunting knife and shooting at civilians without cause. He has since accused the ex-Navy secretary of “meddling in my case” and attempting to smear him throughout the process.

Fox News host Pete Hegseth, a former reserve military officer, said he held private conversations with the president in which he implored him to restore Gallagher’s rank.

Still, veterans said the president should follow established legal and diplomatic frameworks rather than listening to his favourite television network when it comes to matters of military policy.

“There’s a reason we have the Geneva Convention. There’s a reason we have the Universal Code of Military Justice. There’s a reason we have the morale and ethics that we learn in training,” said Josh Manning, a former Army intelligence officer. “For Trump to just step in and undermine centuries worth of morale and discipline undercuts the very military that he’s trying to command.”

The president tweeted on Sunday that he was “not pleased” with the handling of Gallagher’s trial, and that the Navy SEAL had been “treated very badly” despite being “completely exonerated on all major charges”.

“Eddie will peacefully retire with all of the honours that he has earned, including his Trident pin”, the president wrote.

Mr Spencer slammed the president in his resignation letter, released on Sunday, suggesting the president did not share his views for “good order and discipline” in the military.

“The constitution and the uniform code of military justice are the shields that set us apart, and the beacons that protect us all. I have strived to ensure our proceedings are fair, transparent and consistent, from the newest recruit to the flag and general officer level,” the letter read. “Unfortunately it has become apparent that in this respect I no longer share the same understanding with the commander in chief who appointed me.”

Charlotte Clymer, an Army Veteran and press secretary at the Human Rights Campaign, said Mr Trump appeared to be “hell-bent on exploiting” the military justice system for his own purposes.