When historian Richard Immerman concluded a stint as assistant deputy director of national intelligence in 2009, he recalls a pair of government staffers coming in to collect his papers as part of the transfer to a new administration.

After President Trump’s term comes to a close on Wednesday, it’s unlikely that such a handover of documents will be so orderly in various corners of his government—and, especially, in the case of the President himself.

According to Immerman, a Temple University professor and author of several presidential biographies, historians who plan to chronicle the Trump presidency are “petrified” by the task they are facing.

“The inattention of this administration to legal requirements [about preserving records] is unprecedented. I’m pessimistic we’ll get many documents,” Immerman says.

Trump is hardly the first President who has tried to thwart the collecting of records—his 19th-century predecessors often burned their correspondence, while fears that President Nixon would destroy important records led Congress to pass laws to help preserve them. But among Presidents of the modern era, the Trump administration will be particularly difficult to document.

This is partially due to the character of Trump himself; it’s hard to imagine a President who encouraged a mob that stormed the Capitol being concerned about the legal niceties surrounding federal archives. Trump’s penchant for chaos in governing will also make it harder to collect documents from various agencies.

“One of the unique problems with the Trump administration is the constantly changing cast of characters. It will make it more difficult to be confident about the quality of record keeping,” says Immerman.

Another challenge for historians stems from Trump’s reliance on private platforms like Twitter to conduct much of his presidency.

In the wake of the Capitol attack, Twitter deleted the President’s account while the likes of Facebook and YouTube have also shut off a variety of his communication channels. All of this will make the work of the historians harder at the same time as they confront a problem familiar to everyone in the digital age—vast amounts of data, much of it of little importance.

But while the official records of Trump’s presidency are likely to be “a mess,” in the words of Immerman, historians will also be able to tap new resources in piecing together exactly what happened from 2017 to 2021.

Recording a Twitter presidency

The decision by Twitter to delete President Trump’s tweets is especially significant given how the platform spurred his rise to political power and how he used it to shape domestic policy and foreign relations. As one political analyst told the Washington Post, “Without Twitter, there would be no Donald Trump presidency.”

Twitter’s decision to delete the tweets is not the historical catastrophe it might first appear. As a spokesperson for Twitter pointed out to Fortune, a nonprofit site called Politwoops has preserved all of Trump’s tweets, including the many he deleted himself.

Brooks Simpson, a presidential historian at Arizona State University, says such third-party services have done a good job of “faithfully recording” Trump’s tweets. Meanwhile, individual researchers have been working to archive other social media sites, including Parler, a site popular with Trump diehards that was forced offline last week for promoting hate and the Capitol riots.

Such ad hoc initiatives are probably not the optimal way to preserve federal records and are a far cry from the system created by Congress in 1978 in response to Nixon’s presidency. That system introduced two laws, one aimed at collecting the President’s records, and the other at federal employees.

Those laws, especially the one directed at the President, are in large part advisory, however, and do not offer many remedies in the case of an executive branch willing to flout the rule of law. Two groups, American Oversight and Democracy Forward, for instance, sued to force President Trump and the secretary of state to preserve notes related to a meeting with the President of Russia. That lawsuit, and ones like it, fell short after judges found the groups lacked the standing to bring them.

For historians, a new twist on familiar problems

Trump’s Twitter presidency is hardly the first time new technology has thrown a curveball into the quest to preserve presidential records. Simpson, the ASU historian, notes there was a debate over how to handle President Obama’s use of a now-archaic BlackBerry device to communicate.

Before that, the presidencies of JFK and FDR, who respectively made television and radio a defining feature of their administrations, required scholars to turn to private broadcasters to obtain important historical artifacts.

Nonetheless, the challenges of technology have grown more acute in the era of electronic records. Immerman, the presidential scholar, notes that he and other historians have been working to obtain records from the Reagan administration stored on five-inch floppy drives—a task that has so far been unsuccessful because the technology is so antiquated that no one has been able to decrypt them.

The biggest challenge for historians, however, has been the huge and growing volume of digital data. Instead of a tidy bundle of typewritten letters, scholars must contend with an endless volume of email correspondence, most of it insignificant. Meanwhile, a growing number of politicians and their aides are relying on encrypted texting apps like Signal that destroy messages once received—the 21st-century equivalent of burning sensitive letters.

Texts sent on Signal and other ephemeral correspondence is also likely to account for many of the most sensitive and historically significant moments of the Trump presidency. The upshot is that the most interesting (or damning) documents related to Trump are probably gone forever.

Simpson predicts this will lead historians to change how they approach their craft and the sources they use to inform their research.

“The fat comprehensive biographies of U.S. Presidents we’re used to—that’s going to get harder and harder to do,” he says. “Not because of a lack of documentation but because there’s so much information that’s being put together indiscriminately.”

Simpson says an important source for future historians, including those covering Trump, will be the flood of personal memoirs that are appearing in greater number after every administration. He also predicts that the adage “Journalists write the first draft of history” will take on a deeper meaning as more journalists write meaningful historical accounts—and as historians take to the media to share their own reflections on current events.

“The work of historians and journalists is converging,” says Simpson.