The Justice Department’s review of the origins of the Russia probe has become a criminal investigation, a source familiar with the matter confirmed to NPR.

It is unclear what prompted the shift from an administrative review to a formal criminal investigation, when the change took place or what potential crime is under investigation.

The change drew immediate criticism from Democrats, who have accused Attorney General William Barr of turning the Justice Department into a political weapon for President Trump.

“These reports, if true, raise profound new concerns that the Department of Justice under Attorney General William Barr has lost its independence and become a vehicle for President Trump’s political revenge,” said the Democratic chairmen of the House Judiciary and Intelligence committees, Reps. Jerry Nadler of New York and Adam Schiff of California.

“If the Department of Justice may be used as a tool of political retribution or to help the president with a political narrative for the next election, the rule of law will suffer new and irreparable damage,” they said.

Barr tapped the U.S. attorney for Connecticut, John Durham, in May to lead the review. It wasn’t immediately clear whether Durham has impaneled a grand jury or what crime may be suspected.

Barr told Congress earlier this year that he wants to understand how and why investigators made the decisions they did in 2016, when the FBI began to investigate what it later verified was a broad campaign of “active measures” by Russia targeting the U.S. presidential election.

Former special counsel Robert Mueller later documented that interference in hundreds of pages of court documents and in his final report. Thirty-four individuals, including 25 Russian nationals, as well as three Russian entities, were indicted in the investigation.

Mueller’s report documented many connections between Trump’s campaign in 2016 and the Russian interference but did not establish a conspiracy to throw the election.

The investigation also documented a number of episodes following the inauguration that could have been considered obstruction of justice, but Mueller did not make a charging decision because of Justice Department policy that a sitting president cannot be indicted.

Barr, however, concluded that the evidence did not establish that the president obstructed justice.

Black eye for the FBI

At the same time, a number of embarrassing subplots for the FBI and the Justice Department drew intense criticism from Trump and his supporters, who sought to fault investigators and undermine the basis for the Russia investigation.

A key special agent and a top lawyer mocked Trump in text messages on their official government phones during the time they were carrying on an extramarital affair. They were removed, as were other insiders suspected of political bias.

The director and deputy director of the FBI also were removed in the midst of a broader months-long political war over federal law enforcement.

Barr, who became attorney general in this context, told Congress that he wanted to understand why there had been what he called “spying” on Trump’s campaign in 2016 and why neither the candidate nor his top aides were briefed by the FBI about its discoveries about Russian interference.

Trump and Republicans also have pressed Barr to look into a number of other chapters from the imbroglio, including the FBI’s use of confidential human sources; conspiracy theories involving the 2016 cyberattack on the Democratic National Committee; Hillary Clinton and others.

It isn’t clear what Durham is or isn’t investigating or whether he has identified criminal activity.

But the Justice Department said in a letter to Congress in June that the Durham review was “broad in scope and multifaceted, and is intended to illuminate open questions regarding the activities of U.S. and foreign intelligence services as well as non-governmental organizations and individuals.”

But the escalation of Durham’s inquiry into a criminal case is politically important to Republicans, who call the Russia investigation the work of “biased” conspirators within a “deep state” who abused their powers out of political animus toward Trump and his campaign.

The top Republican on the House Judiciary Committee, Doug Collins of Georgia, welcomed the decision to upgrade the Durham probe to a criminal investigation.

“The special counsel’s multi-million dollar investigation concluded that no Americans conspired with Russia in 2016,” Collins said.

“As a result of the empty accusations about this president and what the inspector general found to be political bias at the top tiers of the FBI, Americans have unanswered questions about how the Russia investigation began.”

Connection to the Ukraine affair

The Durham investigation also has become politically important to the White House’s defense of its actions in the Ukraine affair.

Acting chief of staff Mick Mulvaney and other allies of Trump have said it was wholly appropriate for Trump to ask Ukraine’s president and other heads of state for help with U.S. investigations that could uncover wrongdoing.

Mulvaney cited Durham’s ongoing work and the need to answer what Mulvaney called lingering questions as one explanation for why Trump had asked the Ukrainians for investigations.

Trump or Barr also have asked the Italian, British and Australian governments to cooperate.

Democrats now pursuing an impeachment inquiry into the president argue that he abused his office in threatening to withhold engagement and military assistance from Ukraine unless it agreed to launch investigations Trump thought might help him in the 2020 election.

President Trump made a high-profile, short-lived typo this past weekend when he referred to Defense Secretary Mark Esper as “Mark Esperanto” in a tweet that was deleted after an hour.

Trump has made unprecedented use of Twitter from the Oval Office and regularly uses it to share thoughts and announcements on politics and diplomacy. For many experts, his penchant for deletion is cause for concern: Under the 1978 Presidential Records Act, Trump’s electronic communications are considered public property, and living history.

Trump has spoken about the power of Twitter and the political importance of his tweets. He told Fox News’ Tucker Carlson in 2017 that he might not have been elected without the platform and viewed it as an effective means of communication as president.

“My use of social media is not Presidential — it’s MODERN DAY PRESIDENTIAL,” he tweeted in July 2017.

The president’s tweets are an important window into his communications with other politicians, his supporters and the public, said Dan Mahaffee, senior vice president and director of policy at the Center for the Study of the Presidency and Congress.

“Whether you support the president or not, this is similar to how [Franklin Delano Roosevelt] approached fireside chats or how John F. Kennedy used television to relate to his supporters and the American people,” Mahaffee said. “And each time you get into a new technology of communication, that record is very revealing in how technology was used and how the president thought it helped achieve his goals.”

Access to complete presidential records makes fuller historical research and scholarship possible. For instance, new work on the early years of the Cold War is only coming out now that certain documents and parts of the policy record are declassified, Mahaffee said.

Trump’s tweets constitute an important part of the presidential record and should be preserved for the public as such, according to Sarah Quigley, the chairperson of the Society of American Archivists’ Committee on Public Policy. Quigley believes this issue is as much about statutory compliance as it as about democratic health.

“Records of the federal government and of the executive office are how we hold our elected officials accountable for their decisions and for the actions that they take on our behalf and the way that we know what they do … and judge the decisions that they’re making is through access to these records,” Quigley said.

The stakes of Twitter diplomacy

Twitter says about 40% of its 330 million monthly active users visit the site on a daily basis, a relatively small audience compared with those of Facebook and Instagram. But the platform wields disproportionate amounts of influence, experts say, because of who uses it.

“I think that Twitter is an important platform if for no other reason that some very high-profile political figures, the president included, have made it their platform of choice,” said R. Kelly Garrett, a professor at the Ohio State University’s School of Communication who researches online political communication. He compared Twitter to a “personal newswire,” as journalists amplify what politicians tweet.

The president joined Twitter as @realDonaldTrump in 2009, well before he officially entered politics. And though he inherited the @POTUS account upon inauguration, the president has continued to tweet from his original handle, so the official account consists mostly of retweets from his personal account.

According to Shontavia Johnson, an attorney who focuses on the intersection of law and social media, Trump’s tweets should be considered part of the presidential record no matter which account publishes them because of their political import and historical significance.

She cited examples of such tweets from the last several years: one stating Mexico would reimburse Americans for Trump’s proposed border wall, one accusing China of stealing a U.S. Navy research drone, one rebuking then-British Prime Minister Theresa May but tagging the wrong username, and one disparaging the Electoral College system.

“Even though it’s a ‘unofficial’ Twitter account, it is being used to create or provoke responses that certainly have diplomatic national ripple effects,” Johnson said. “So I don’t think the fact that it’s @realDonaldTrump means that those tweets are not presidential records.”

The reason for the record

Congress passed the Presidential Records Act in 1978 out of concern that President Richard Nixon would destroy the tapes that ultimately led to his resignation. The law designated records of the president and executive office as public property and established guidelines for their preservation.

The act defines presidential records as any materials created or received by the president “in the course of conducting activities which relate to or have an effect upon the carrying out of the constitutional, statutory, or other official or ceremonial duties of the President.” It excludes personal records like diaries and allows presidents to dispose of certain public records “once the views of the Archivist of the United States on the proposed disposal have been obtained in writing.”

Prior to the act, presidents could do whatever they pleased with their papers upon leaving office, said Johnson. Many intentionally destroyed their record to protect their personal privacy or national security interests. President Calvin Coolidge destroyed most of his personal papers, leaving his private secretary scrambling to preserve whatever he could. Even some of President Abraham Lincoln’s papers were destroyed by his son, Johnson said.

Franklin Delano Roosevelt established the informal tradition of donating his presidential records back to the people in the form of a presidential library, according to Quigley. This tradition was formally codified by the Records Act.

The Presidential and Federal Records Amendments of 2014 expanded the PRA’s definition of records to include electronic content, which Johnson said has been interpreted as an umbrella term encompassing text messages, emails, social media and the like.

“It’s not the media that makes it a record, or the platform, it’s the content,” Quigley said. “A presidential record is anything — any record, on any platform or in any media — created by the president or his office in the conduct of his business as president. And all of those records are considered permanent by the National Archives and the Presidential Records Act.”

Archives in the digital age

President Barack Obama was the first to tweet as @POTUS, and his administration complied with the 2014 amendments by auto-archiving his posts. It also published a searchable archive of Obama’s tweets shortly before he left office in January 2017.

Obama used Twitter unprecedentedly, but differently than his successor did. He joined Twitter as @BarackObama in 2007, though a White House spokesman said Democratic National Committee staffers authored posts from that account. Obama also tweeted through the @WhiteHouse account, which was run solely by White House staffers until 2011, when he started writing and initialing his own occasional tweets.

It is unclear how the Trump administration is preserving his tweets, according to experts.

Then-White House Press Secretary Sean Spicer said in 2017 that Trump’s tweets should be considered official statements. Kelly Love, then a White House spokeswoman, told CNN that same year that the administration had “systems in place to capture all tweets and preserve them as presidential records; even if they have been deleted,” but it did not elaborate on whether those systems applied equally to both accounts.

In 2017, Sens. Claire McCaskill and Tom Carper voiced concerns about the Trump administration’s compliance with the Records Act in a letter to Archivist of the United States David Ferriero. They specifically asked whether the National Records and Archives Administration had determined if Trump’s altered or deleted tweets constituted presidential records.

Ferriero responded that “records management authority is vested in the president” and that the agency does not make such determinations but rather “provides advice and guidance concerning the Records Act upon the request of the White House.”

“NARA has advised the White House that it should capture and preserve all tweets that the President posts in the course of his official duties, including those that are subsequently deleted, as Presidential records, and NARA has been informed by White House officials that they are, in fact, doing so,” Ferriera wrote.

When asked about preserving the president’s tweets, including deleted tweets, the White House told NPR in a statement, “The White House complies with the relevant records laws, including as they apply to social media platforms.”

Official guidance on presidential records preservation says records are automatically transferred to the legal custody of NARA and the Archivist of the United States at the end of each administration. The Records Act permits public access to these records after five years, and they will ultimately be preserved and housed in a presidential library.

This means the extent of the Trump administration’s records preservation may not be apparent for some time. Once established, digital and physical archives are governed by the same rules and restrictions, Quigley said, even if digital records are easier to access.

“Generally speaking, the access policies are the same with that one difference where digital records are already digital and don’t require reformatting to make them available online,” Quigley said.

Pros and cons of the Internet stepping in

In the meantime, several grassroots entities have taken it upon themselves to document Trump’s tweets.

Websites such as Trump Twitter Archive and Factba.se have archived the president’s Twitter account in its entirety, and the Politwoops database, which is maintained by ProPublica and the Sunlight Foundation, preserves the deleted tweets of Trump and other politicians.

“I think it’s natural that in a digital era, one that gives us Wikipedia, you’re going to see a lot more crowdsourcing of presidential history, presidential records,” said Mahaffee, of the Center for the Study of the Presidency and Congress.

Experts expressed mixed views on these grassroots efforts.

Quigley, from the Society of American Archivists, said she understands why ordinary citizens may distrust the government and want to hold it accountable themselves, but believes they should not have to.

“It’s always heartening when citizens or activist organizations sort of get involved in these issues and take responsibility for the preservation and maintenance of these documents, and recognize their ongoing value,” Quigley said. “But the fact remains that this is an obligation of the executive office and it is not the responsibility of the people to be doing this work.”

Johnson said while these websites and databases perform an important function, they could have “unintended consequences.” For example, she said, presidents prior to the digital age had more “wiggle room” to make mistakes such as typos in their communications with the public. And while she believes preserving this record is important, she recognizes that digitally documenting every typo “creates so much information that sometimes it can be hard for people to understand the importance of it.”

What’s next for presidential records preservation?

Because each president has their own relationship to NARA and the Records Act, it is unclear what, if any, precedent the Trump administration is setting with its handling of tweets.

Presidents have always been reluctant to make their records public, and in that sense, this is nothing new, Quigley said. For example, President George W. Bush signed an executive order in 2001 that limited the public’s ability to access presidential records. It was revoked by President Barack Obama in 2009.

“The difference with President Trump is that he uses Twitter in a way that no one has before, and is using it as a policy platform in a way that other presidents have not,” Quigley said. “And that makes it a more critical document.”

If future presidents continue to use the platform this way, the importance of archiving and accessing tweets will grow, Quigley said.

The Records Act provides guidance for record management but offers no way to check or enforce the executive office if it does not comply, Johnson said. She pointed to a 2017 case pending on appeal to the D.C. Circuit Court that alleges in part that Trump’s deletion of tweets violates the Records Act. While the U.S. District Court acknowledged the underlying arguments had merit, it dismissed the case because it lacked “a valid cause of action … to proceed to the merits.”

“The law creates a really clear system, but it’s a system that can’t be checked once the President makes a decision to create, manage or delete a given record,” Johnson explained. “It really doesn’t give private citizens a way to sue the president if they think he’s violated any of the standards within the act.”

There have also been recent legislative efforts to modernize the Records Act. Rep. Mike Quigley, D-Ill., introduced the COVFEFE Act — an acronym drawn from one of Trump’s most well-known, ultimately-deleted tweets — in 2017, which would explicitly include the term “social media” in the Records Act.

Mahaffee believes amending the Records Act is important but “low-hanging fruit,” as technology will always move faster than law. He said it comes down to a culture of transparency that presidents should be cultivating in their administrations from their first day onward.

“The challenge is when you write a very prescriptive law regime, how do you ensure that you have the flexibility for, you know, God forbid, who’s going to be the first president or candidate on TikTok?” Mahaffee said.

Rachel Treisman is an intern on NPR’s National Desk.