Washington (CNN) President Donald Trump, as he considers pardoning military personnel accused of murder and other crimes , is following a pattern for wielding his clemency power that relies more on his personal interest in a case and its odds of galvanizing his political base than on the careful legal procedures used by his predecessors.

If granted, the military pardons Trump is considering would come after lobbying efforts from Republican members of Congress and persistent coverage in conservative media, where the cases are cast as the result of overzealous prosecutors and a military tainted by political correctness.

US presidents have long granted pardons or commutations to political allies or in cases taken up by their supporters. Still, the practice has grown more apparent under Trump, who is regularly guided by what he sees on television and through conversations with lawmakers and outside advisers.

In the case of the American military members who may be granted pardons after committing offenses that could be described as war crimes, the consideration has drawn criticism from those who believe it could undermine the military's system of justice and command structure, as well as undercut US moral standing abroad.

The Justice Department pardon office asked the US military for case files for at least two US service members accused of premeditated murder, including a Navy SEAL, Special Operations Chief Edward "Eddie" Gallagher, and Army Major Matt Golsteyn, three US officials told CNN.

Trump's interest in the possible pardons was first reported by The New York Times , which also said the Trump administration had made requests for expedited pardon paperwork for a group of Marine Corps snipers accused of urinating on the corpses of Taliban fighters. The newspaper said the administration had requested the process be complete by Memorial Day in time for a presidential announcement.

As seen on TV

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Gallagher's case has been championed by dozens of members of Congress, including some of Trump's staunchest supporters in the House of Representatives. In March, Trump discussed the matter with Rep. Ralph Norman, a South Carolina Republican, who tweeted about their conversation afterward.

Trump himself later tweeted that Gallagher would be moved to less restrictive confinement -- "In honor of his past service to our Country," he wrote -- adding Norman's Twitter handle and the handle of the morning television show "Fox and Friends," which has covered the matter extensively.

Last week, another Republican lawmaker, Rep. Duncan Hunter, said he was planning to ask the President to pardon Gallagher if he is found guilty in the murder of an Iraqi war prisoner, citing new combat footage from a helmet camera.

Hunter's office said on Monday the congressman hadn't spoken to Trump about a pardon for Gallagher, but "is hopeful that President Trump does take this action, it certainly is warranted."

Gallagher faces a slew of accusations connected to violations of military law while he was deployed to the Iraqi city of Mosul in 2017, including a charge of premeditated murder in the stabbing death of an injured person in Iraq. Gallagher has pleaded not guilty.

Eyewitness accounts by fellow service members state that during an unprovoked attack in Iraq, Gallagher stabbed and killed an unarmed detainee, then posed for a photo holding the dead prisoner's head up by the hair while brandishing a knife. Gallagher's attorney has said he will present evidence that Gallagher, according to his own account, moved against the man when he made a sudden move.

But the prisoner was not armed, was in custody and, according to a January ruling by a military judge, there is an eyewitness who saw Gallagher stab the man in the neck several times.

To Gallagher's champions in Congress, the case is an example of US troops being punished for doing the very job they were sent to war to do -- kill terrorists. Conservative media outlets, including Fox News, have provided extensive coverage of the issue, including in the past week as the pardon paperwork was being requested by the Trump administration.

Last Tuesday, Gallagher's wife appeared on "Fox and Friends" after her husband's lawyers accused military prosecutors of spying on them through tracking software embedded into emails.

"Now it's going to be a matter of who is going to start investigating these investigators," Andrea Gallagher said, echoing a refrain Trump himself has made regarding his own legal mire involving Russian election interference.

Factors at play

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The ability to grant pardons or commutations is one of the most unlimited of a president's constitutional powers, and there are no set laws in how they can be wielded. There are, however, precedents that past White Houses have followed in choosing applicants for clemency.

The Justice Department's Pardon Attorney office spells out an extensive application process, including for military offenses, that requires a five-year waiting period "designed to afford the petitioner a reasonable period of time in which to demonstrate an ability to lead a responsible, productive and law-abiding life."

The office also says that when considering applications, "pardon officials take into account the petitioner's acceptance of responsibility, remorse, and atonement for the offense."

Those have not been abiding features of Trump's pardon selection process. The first person he pardoned, Sheriff Joe Arpaio, was defiant despite being convinced of criminal contempt of court.

Others came to Trump's attention not through applications to the pardon attorney but in their stature as high-profile conservatives -- such as Scooter Libby , former aide to Vice President Dick Cheney; Dinesh D'Souza , the commentator who pleaded guilty to making illegal campaign contributions; and Conrad Black, the Trump supporter , biographer and white collar criminal who Trump pardoned last week.

When it comes to military offenses, Trump has shown a willingness to pardon service members accused of murder while serving in war zones. Earlier this month he pardoned Michael Behenna, a former Army first lieutenant who was sentenced to prison in 2009 for killing an Iraqi prisoner.

To some, a batch of military pardons for serious crimes could damage both the military's ability to uphold its own rules and erode American moral authority.

"I think he's sending a message," said Waitman Wade Beorn, a combat veteran who served in Iraq and a Holocaust and genocide studies historian at the University of Virginia. "Soldiers do what the leadership tells them, or signals to them, is most important to them. And I think its clear in this case you have the President, who also functions as the commander-in-chief, sending a message that he disagrees with decades, even centuries of legal precedent in the law of war."

"It makes us sound very hypocritical in countries where were trying to help them develop the same kinds of moral, ethical military behavior that we try to model," Beorn said. "I think in many ways it encourages our enemies, enemy combatants, to behave in a similar form. If we're not abiding by our own self-professed values, then why should they?"

Lobbying from within

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US officials said the Trump administration has also requested files involving the case of Army Major Matt Golsteyn, a Special Forces soldier and Afghanistan veteran charged in a 2010 killing of a suspected bomb maker in Afghanistan as part of a battle in Helmand Province. His lawyer has maintained the death occurred during a mission ordered by his superiors.

The Army has been investigating the killing intermittently since 2011, and, like Gallagher's case, has been featured during segments on Fox News. Golsteyn was interviewed in February by the channel's weekend morning host Pete Hegseth, who Trump once considered as a potential Veterans Affairs secretary and who has phoned into policy meetings at the White House.

Trump tweeted in December that he was reviewing the case.

"At the request of many, I will be reviewing the case of a 'U.S. Military hero,' Major Matt Golsteyn, who is charged with murder," Trump wrote. "He could face the death penalty from our own government after he admitted to killing a Terrorist bomb maker while overseas."

The New York Times reported the administration was also reviewing the case of Marine Corps snipers who shot video of themselves urinating on corpses of Taliban fighters and later posted it to YouTube. Some members of that group were subject to court martial proceedings and were demoted in rank.

But the case was later appealed when it was discovered Gen. Jim Amos, then serving as the commandant of the Marine Corps, told a colleague he wanted the Marines seen on tape desecrating the corpses "crushed" for the actions, creating the appearance of unlawful influence. One of the convictions was overturned.

Those who took up the cause of the Marine snipers included John Dowd, who represented one of the snipers involved in the case and later served for a time as Trump's lead lawyer in the special counsel investigation.

He was serving in that capacity in 2017, when one of the Marine sniper convictions was overturned on appeal. He said at the time he would file a petition to have the other punishments in the case handled similarly.

Another of Trump's inner circle -- Marine Gen. John Kelly, who served as Trump's second chief of staff -- was also indirectly linked to the case. He testified in the defense of one of the snipers during a 2013 proceeding, and followed the issue closely.