(CNN) President Donald Trump just appointed himself America's judge and jury, casting even deeper doubts on whether the nation's impartial justice system can withstand his expanding political assault.

"I'm actually, I guess, the chief law enforcement officer of the country," Trump said Tuesday, after setting off alarm bells with a flurry of pardons and commutations

Though the President is the head of the executive branch, America's real chief law enforcement official is William Barr and there are dramatic signs that even the loyal attorney general is beginning to feel the strain of the last week's legal tumult.

CNN's Kaitlan Collins reported Tuesday night that Barr had considered resigning over Trump's interference in his department, including the President's tweets that he said last week made it impossible for him to do his job. The story was first reported by the Washington Post

The President's relish in unveiling a new set of clemency decisions in highly sensitive political cases -- days after his meddling in the Roger Stone sentencing recommendations -- is only exacerbating a Justice Department credibility crisis. That is especially the case since his presidency has unfolded in a whirl of scandal, legal showdowns and questionable constitutional power grabs that are hardly conducive to good governance and respect for the impartiality of the Justice Department.

Trump on Tuesday commuted the jail sentence of Rod Blagojevich, the ex-Illinois governor convicted of trying to sell off the Senate seat once held by former President Barack Obama, among other crimes. He pardoned Bernie Kerik, the former New York police commissioner who was convicted of tax fraud. And in another controversial move, he pardoned a fellow kingpin of 1980s New York, the junk bond entrepreneur Michael Milken, convicted of conspiracy to hide stocks and tax fraud.

The moves were the latest examples of Trump's willingness to use his pardon power -- that many Presidents only fully utilize on the way out of the Oval Office door -- to political advantage in the middle of his administration.

His aggressive use of constitutional but still highly provocative presidential power also sparked speculation he would next move to political associates caught up in the Russia probe. And it was the latest extraordinary example of untamed executive power that suggests the President is feeling invincible now he has been delivered from the impeachment storm.

Tuesday's developments were also a fresh indication that he is intensifying his attacks on institutions that challenge his power, with the courts becoming an increasingly frequent target.

"What the President has discovered is that he can do pretty much whatever he wants, within reason," Renato Mariotti, a former federal prosecutor told CNN.

Trump's latest moves are likely to alarm critics who see his own questionable legal behavior and record of stretching his powers to the limit as a historic threat to the US legal system. More than 2,000 former prosecutors have signed onto a letter calling on Barr to resign for facilitating the President's legal maneuvering. And a group of judges also called an emergency meeting to discuss political threats to the integrity of the legal system, after years of threats from the President.

Trump stuns with audacity of pardons

But Trump, brazen and unapologetic, announced a flurry of commutations and pardons on Tuesday.

His willingness to intervene in highly charged political cases threatened to obliterate the invisible wall erected between the White House and the Justice Department since the Watergate era -- explicitly designed to avoid suspicions of such interference.

The White House did not provide evidence of a detailed pardon process conducted through the Justice Department, and the President did not explain his decisions at length other than to describe the prosecutions as "unfair" and sentences very tough.

Tuesday's moves were only the latest examples of Trump's willingness to use pardons for political advantage.

In 2017, for instance, the President pardoned conservative icon and former Arizona sheriff Joseph M. Arpaio who was convicted of criminal contempt over his harsh immigration policies. He also pardoned I. Lewis "Scooter" Libby , the chief of staff to former Vice President Dick Cheney who was convicted of perjury and obstruction of justice in a case over the leaking of a former CIA officer's identity.

The President's latest decisions came two days before his political trickster, Stone, is due to be sentenced, and days after the Justice Department reversed recommendations for how long he should spend in jail following Trump's angry complaints.

"I'm allowed to be totally involved," the President told reporters before heading off on a western campaign swing.

Trump is undoing years of government prosecutions

In the last few days, in a new activation of always-implied presidential powers, Trump has effectively assumed the authority to undo complex prosecutions, ignore jury decisions and usurp government prosecutors who put years into high-profile cases.

In the process, he's sent a message that convicts with associates who are close to the President politically -- or who can get on Fox News -- will enjoy a more lenient form of justice.

Kerik, for example, is a protege of Trump's personal lawyer Rudy Giuliani — who was at the center of the effort to get dirt from Ukraine on Trump's opponents that led to his impeachment.

Blagojevich's wife has often taken to the President's favorite conservative news network to plead his case. And the White House noted in a statement that Milkin's philanthropy had led conservative heroes like Giuliani, Sheldon Adelson and House Republican leader Kevin McCarthy to support calls for a pardon.

Trump's recent interventions in the legal process also opened a window into the President's personal morality and the principles which govern his own attitudes to power.

Kerik, Blagojevich and Milken were all convicted of offenses that the President has been accused of committing by his enemies. Their cases involved a blizzard of abuses of power, betraying public trust, soliciting quid pro quo, fogging tax records and lying to investigators.

It is almost as if Trump is arguing implicitly that such corruption should not be criminal at all, but is the normal behavior of powerful men -- such as himself.

It was also notable that Trump specifically noted that Blagojevich was put behind bars by US Attorney Patrick Fitzgerald, a star legal contemporary of Trump's nemesis, fired former FBI Director James Comey. Fitzgerald prosecuted Libby as well and also joined Comey's legal team in 2017. That the President appears to be taking aim at those associations seems unlikely to be a coincidence.

Trump's swipe also represented an escalation of his war on government prosecutors in general -- four of whom walked off the Stone case after the Justice Department capitulated to his wishes last week.

The President has spent years building a conceit that the instruments of impartial justice are in fact themselves corrupt and that their investigations into his own and his associates' transgressions are part of a deep state plot to overthrow him.

It would surprise no one in Washington if, having prepared the public for aggressive interventions in the legal system, the President turns to cases that reflect on him directly, like those against Stone, jailed former campaign chairman Paul Manafort and disgraced former national security adviser Michael Flynn

The President insisted on Tuesday that he had not even thought about pardoning Stone -- an assertion that was being treated with skepticism in Washington Tuesday night.