President Trump has rattled national security experts with his use of executive authority. (YURI GRIPAS/Reuters)

President Trump’s exercise of his executive powers, particularly in matters of national security, is increasingly unsettling an array of legal scholars, including conservatives, who say it risks corroding the office of the presidency and has roiled relations between the White House and other agencies.

Over the past year, Trump has — without consulting the Office of the Pardon Attorney — granted clemency to a number of individuals, including his political ally Joe Arpaio, the former Arizona county sheriff convicted of criminal contempt related to his department’s targeting of undocumented immigrants.

Last month, Trump revoked the security clearance of former CIA director John Brennan, one of his harshest critics, who has called “treasonous” Trump’s validation of Russian President Vladimir Putin at the expense of U.S. intelligence agencies that concluded Moscow sought to help Trump win the White House.

And this month, Trump ordered the declassification of law enforcement material linked to the investigation by special counsel Robert S. Mueller III into Russia’s interference in the 2016 election, a move the president eventually walked back after protests from the Justice Department and foreign allies.

Constitutionally, such actions are defensible. But the president is “eviscerating precedent and procedure,” said David Rivkin, a conservative constitutional lawyer who was an attorney in the George H.W. Bush and Reagan administrations.

“As far as the mechanics of government are concerned, it is creating anger and disharmony on both the side of the political masters and the career people,” he said. “It breeds resistance. It’s negative synergy.”

Trump’s un­or­tho­dox approach — taking actions, in many cases, without consulting key advisers — may bring a much-needed shake-up to the federal bureaucracy, some conservative scholars say. But others say it not only risks eroding the norms of government, but also may lead Congress and the courts to erect guardrails that constrain the presidency, leaching it of the flexibility integral to its effectiveness.

“If Congress inserts itself into these national security processes as a reaction to the way he’s exercising the powers of his office, then the institution of the presidency will actually be left much weaker than he found it,” said Carrie Cordero, who was a senior Justice Department national security lawyer in the George W. Bush and Obama administrations.

Cordero suggested that, should Democrats retake Congress after November’s elections, they may seek to put restraints on Trump by pursuing legislation that bars the president from firing a special prosecutor or requiring that the chief executive first consult the Justice Department before granting pardons.

To be sure, some national security experts defend the president’s actions as a healthy antidote to the bureaucracy, which they feel has grown too independent.

“Shouldn’t we look, every couple of administrations, at least, at the structure of the executive bureaucracy and ask ourselves, ‘Is it working the way it should work?’ ” said Charles Kesler, a government professor at Claremont McKenna College.

He cited the security clearance issue as an example.

“Security clearances are supposed to be granted to those who have a need to know in order to plan and execute foreign policy,” he said. “It’s hard to imagine that John Brennan, who is calling the president a traitor, has a need to know after he has left office. . . . I don’t think it’s irrational or unseemly to revoke his clearance.”

The president, nonetheless, has taken to the power he is afforded under Article II of the Constitution, which outlines the scope of authorities granted to the office. He has sought to ban transgender men and women from serving in the military. He fired his FBI director, James B. Comey, who had been in charge of the Russia probe, leading to Mueller’s appointment as special counsel.

“The structure of national security is one of empowering executive discretion cabined by congressional and judicial oversight,” said Paul Rosenzweig, a senior fellow at the R Street Institute, a self-described “center-right” think tank, and a senior homeland security official in the George W. Bush administration. “When the president acts within the normal bounds of behavior, the ability of the Cabinet and Congress to look over the shoulder is enough. When he diverges from the norms, the grant of discretion creates an opportunity for mischief, if not maliciousness.”

National security experts were unnerved by Trump’s use of his pardon power. No modern president has exercised it as he has — that is, so early and frequently in a presidency and mostly without input from the Justice Department’s pardon attorney, who reviews clemency petitions and makes recommendations to the White House based on applicants’ post-conviction conduct, their character, acceptance of responsibility and remorse.

Trump pardoned Arpaio, who faced up to six months in jail for defying a court order, in August 2017 — before the former sheriff was even sentenced. The move fanned speculation that the president was signaling his willingness to look out for associates who might be charged in the Russia investigation.

“I’d be the first to say that the use of the pardon power with Sheriff Joe was obviously not within the purpose that the framers hoped,” said John Yoo, a law professor at the University of California at Berkeley and Justice Department official in the George W. Bush administration. “It’s petty, foolish, unnecessary. But it doesn’t really harm the long-term interests of the country. If he pardoned Paul Manafort, then I would be worried.”

Manafort was Trump’s campaign chairman until August 2016 and came under investigation for past consulting work for Ukraine’s pro-Russian ruling party. In August, he was convicted of financial fraud linked to that lobbying work and has pleaded guilty to obstructing justice in Mueller’s probe. As part of his plea agreement, Manafort is cooperating with the special counsel.

Trump has declined to say whether he would pardon Manafort, though he has called the trial a “very sad day for our country” and Manafort “a very good person.”

Stripping Brennan of his security clearance was widely seen as political retaliation , a slap at a senior intelligence official who has taken to Twitter and cable news to attack the president’s agenda and discredit him. Critics of Trump’s decision, even those who feel Brennan’s antagonism toward the president has been excessive, said Trump should have consulted the CIA, which issued the clearance.

“It’s just unseemly,” Rivkin said. “You’ve got to work through the system. You cannot just say, ‘I’m going to strip clearances on my own.’ It sets up a pernicious dynamic. He absolutely can do it, constitutionally, but it is not wise.”

Trump has threatened to revoke the clearances of others who have raised his ire, including Comey, FBI deputy director Andrew McCabe and Justice Department official Bruce Ohr. Each has played a role in the Russia probe.

Trump fired Comey in May 2017, a move his critics suggest was intended to end the investigation. The president celebrated McCabe’s firing earlier this year amid allegations he misled officials conducting a leak investigation. And Trump suggested that Ohr, who has been linked to a dossier suggesting a conspiracy between the Russian government and the Trump campaign, should be terminated as well.

“The common thread, of course, is that all of these people are associated in some way, in his mind at least, with what he refers to as the ‘witch hunt,’ that is, the investigation of his campaign, or him, and ties to the Russians,” said David Kris, a Justice Department official in the George W. Bush and Obama administrations. “So there you see self-interest coming to the fore.”

National security experts were stunned once more when Trump ordered the declassification and public release of sensitive law enforcement documents central to the Russia probe’s origins, including the application to wiretap Carter Page, a Trump campaign adviser.

The wiretap application was made under the Foreign Intelligence Surveillance Act, which governs the surveillance of suspected spies and terrorists on U.S. soil. Until this year, no FISA application had ever been made public, on grounds that such documents contain details that could compromise espionage and terrorism investigations, expose informants and put them at risk.

“Look, there is absolutely an overclassification problem in the U.S. government,” said Susan Hennessey, a Brookings Institution fellow and former lawyer in the National Security Agency Office of General Counsel. “But there is information that is genuinely and appropriately classified, and when it’s disclosed, it has immediate consequences.”

Four days after issuing his latest declassification order, the president retreated. Instead, the Justice Department’s inspector general has been directed to conduct an expedited review of the documents. In a tweet, Trump said “key allies” expressed concerns about the documents’ release and that Justice Department officials told him that releasing the material without review could adversely affect the Russia probe.

The president undoubtedly has the legal authority to declassify and even shift the balance between secrecy and transparency, but doing so in this instance is inappropriate, as the records Trump wants released relate to a probe of which he is a subject, Kris said.

“It is very corrosive to the rule of law when it looks clear that the reason he is shifting is not because he has made some broad policy judgment about what lies in the national interest,” he added, “but to serve his own self-interest or for partisan political gain.”