(CNN) Donald Trump and his lawyers are staking out a vision of an unrestrained and all-powerful presidency in a staggeringly audacious defense of his actions related to the Russia probe already shared with special counsel Robert Mueller.

The letter, which a source told CNN Trump reviewed and approved before it was sent in January, includes the caveat, "Of course, the President of the United States is not above the law," but then makes an argument that implies that he is, in fact, exactly that.

A Monday morning Trump tweet will exacerbate concerns that the commander in chief believes he is not answerable to the law and that he could terminate the Mueller investigation or escape consequences if wrongdoing is unearthed by the probe, which is examining alleged collusion between Trump's campaign and Russia and whether the President obstructed justice.

"As has been stated by numerous legal scholars, I have the absolute right to PARDON myself, but why would I do that when I have done nothing wrong? In the meantime, the never ending Witch Hunt, led by 13 very Angry and Conflicted Democrats (& others) continues into the mid-terms!" Trump wrote.

As has been stated by numerous legal scholars, I have the absolute right to PARDON myself, but why would I do that when I have done nothing wrong? In the meantime, the never ending Witch Hunt, led by 13 very Angry and Conflicted Democrats (& others) continues into the mid-terms!

Comments by Trump's lead lawyer Rudy Giuliani on Sunday on the question of whether Trump could pardon himself to end the investigation and on the impossibility of a President being indicted also suggest a brazen interpretation of the scope of presidential power.

Sunday's developments cement a trend evident ever since Trump entered the White House: his notion that presidential power is sweeping and unfettered. In his words and actions, Trump has shown little patience for unwritten norms and customs that have acted to constrain the authority of his office over the last two centuries.

By implication, the letter, published by The New York Times on Saturday, argues that the President is within his rights to shut down an investigation into his own conduct and to pardon associates accused of criminal action while avoiding consequences to himself.

"I think those legal arguments are extreme and they are really ridiculous," Renato Mariotti, a former federal prosecutor, told CNN's Ana Cabrera.

"The reason that these positions have never been taken before is that they are very much outside the mainstream," he added. "These are dangerous views."

In recent days alone, Trump has offered repeated evidence of his willingness to claim and wield broad presidential power.

He has imposed fierce pressure on the FBI and the Justice Department over the Russia probe, ignoring the firewall that commonly exists between the White House and such agencies to avoid the impression that the administration of justice is politicized.

JUST WATCHED Trump suggests he may get involved with DOJ Replay More Videos ... MUST WATCH Trump suggests he may get involved with DOJ 03:57

Last week, Trump pardoned conservative commentator Dinesh D'Souza after bypassing pardon vetting procedures typically conducted by the Department of Justice.

The extraordinarily broad interpretation of presidential authority in the letter raises the question of the motivations of Trump's lawyers.

"I assume it is part of a strategy that when they actually do act, they will act somewhat short of those claims so people will be relieved that the President didn't pardon himself," said CNN political analyst David Gergen, a former adviser to Democratic and Republican presidents. "But at the same time he may do what exactly he really wants to do and that is to pardon a number of people so they won't flip."

The arguments of Trump's lawyers are also likely motivated by a long-term goal of sparing the President the ordeal of testifying under oath, a scenario many of his allies believe would be a disaster given his proclivity not to tell the truth.

Giuliani might have inadvertently tipped his hand when he said on ABC News' "This Week" that the President should not testify before Mueller because "our recollection keeps changing."

Outrageous claim

JUST WATCHED NYT: Trump lawyers make case in memo to Mueller Replay More Videos ... MUST WATCH NYT: Trump lawyers make case in memo to Mueller 01:15

The audacity of the lawyers' presentation may also be calculated to convince Mueller not to mount a legal effort to compel the President's testimony -- a struggle that could add months to his investigation.

But it is open to question whether a court would accept many of the positions in the letter, which is characterized more by advocacy than demonstrated legal precedents.

For instance, the lawyers argue in a discussion about the case of fired former national security adviser Michael Flynn and the subsequent firing of Comey that a President, by definition, cannot obstruct justice given his position as the nation's ultimate legal authority.

"The President's actions here, by virtue of his position as the chief law enforcement officer, could neither constitutionally nor legally constitute obstruction because that would amount to him obstructing himself, and that he could, if he wished, terminate the inquiry, or even exercise his power to pardon if he so desired," the letter argued.

Such a bold assertion of presidential power is highly controversial.

"It's an outrageous claim, it's wrong," said former New Jersey Gov. Chris Christie, who is a Trump ally and former prosecutor.

Many legal scholars dispute the idea that a President cannot obstruct justice. While Trump did have the authority to fire Comey, the question becomes whether he had corrupt intent in doing so -- the issue at the center of Mueller's obstruction investigation.

A Brookings Institution study in October concluded that the President's authority to fire the head of the FBI in this case was a "red herring."

"The fact that the president has lawful authority to take a particular course of action does not immunize him if he takes that action with the unlawful intent of obstructing a proceeding for an improper purpose," the report said.

The notion that a President could wield his own power to end an investigation into himself with impunity would meanwhile appear to contradict the core purpose of the nation's founders, to ensure that the presidency did not adopt the unfettered authority of the monarchy that it replaced.

'Self-executing impeachment'

JUST WATCHED Cooper questions Trump's intent with pardons Replay More Videos ... MUST WATCH Cooper questions Trump's intent with pardons 02:50

Giuliani's decision to even discuss the notion that the President could pardon himself also whipped up a storm.

He said on "This Week" that Trump "probably does" have the power to pardon himself, but he insisted the President would not do so and noted troubling political ramifications of any such action.

Preet Bharara, the former US attorney for the Southern District of New York who was fired by Trump, warned on CNN's "State of the Union" that such a move would be tantamount to "almost self-executing impeachment."

This is not the first time that the idea of a President pardoning himself has been mooted.

Former President Richard Nixon took steps to examine the question during the Watergate scandal only to see his own Justice Department advise him that he could not do so on the grounds that "no one may be a judge in his own case."

Nixon encapsulated his view, which is mirrored by Trump's lawyers in their letter to Mueller, by telling David Frost after he left office, "When the President does it, that means it is not illegal."

Giuliani also advanced the case that Trump could escape sanction for any actions he takes as President by telling HuffPost that Trump hypothetically could have shot Comey in the Oval Office to end the Russia probe and not face prosecution for it while in office.

The former New York mayor was making a wider point that the proper remedy for presidential wrongdoing is the Constitutionally provided procedure of impeachment.

"If he shot James Comey, he'd be impeached the next day," Giuliani said to HuffPost. "Impeach him, and then you can do whatever you want to do to him."

Giuliani did not immediately return CNN's request for comment on his statement.

In 2000, the Justice Department's Office of Legal Counsel i ssued a memo concluding that the job of the President is so important that he has effective immunity from being indicted and criminally prosecuted while in office. The Supreme Court, however, has not definitively resolved the question.

CORRECTION: This story has been updated to reflect the timing of Nixon's interview with Frost.