What does it mean to violate the Espionage Act

When FBI agents seized 11 sets of top-secret and sensitive documents from former President Trump‘s Florida residence Mar-a-Lago, per a search warrant revealed on Friday, it was an unprecedented moment—but one that could be traced back to a law that’s more than a century old.

The warrant shows that the agency is investigating whether Trump violated the Espionage Act of 1917. Senator Rand Paul, a Kentucky Republican, was quick to call for a repeal of the law, dismissing it as outdated. “The espionage act was abused from the beginning to jail dissenters of WWI,” he tweeted. “It is long past time to repeal this egregious affront to the 1st Amendment.”

But while the law—which was designed to prevent the unlawful retention of information about national defense, which a foreign enemy could use to harm the U.S.—passed during World War I, to crack down on people who criticized the war, NPR reports that lawmakers repealed the strict censorship sections of the law in 1920.

And perhaps it’s not entirely surprising that the law would find a new spotlight today, at another moment rife with fears about a betrayal of the U.S.

Read more: Analysts Warn Violent Rhetoric After FBI Mar-a-Lago Search Is a Preview of What’s to Come

As TIME has previously reported, World War I amplified xenophobia and fears that immigrants would inspire an uprising akin to the Russian Revolution, which started in 1917. In 1918, Eugene V. Debs, Socialist Party presidential candidate, was arrested and sentenced under the Espionage Act to 10 years in prison after being accused of delivering a speech designed to cause “disloyalty” and “insubordination.”

“There was a crackdown on dissent, and simple criticism of the government was enough to send you to jail,” Christopher M. Finan, author of From the Palmer Raids to the Patriot Act: A History of the Fight for Free Speech in America, told TIME.

Following the war, a combination of job losses and high inflation only exacerbated those fears, and employers were on heightened alert for communist infiltration when more than 3,600 workers went on strike in 1919.

Prosecutions under the Espionage Act have been relatively rare. Notable uses of the law include the 1957 arrest of Colonel John C. Nickerson Jr., “the first American to be prosecuted for leaking top-secret national security information to the press,” according to historian Sam Lebovic. As Lebovic detailed in an article for Politico, Nickerson supervised a missile program and agents discovered unsecured classified documents in his Huntsville, Ala., home. In the 1970s, Daniel Ellsberg faced charges under the Espionage Act for leaking the Pentagon Papers, but a judge dismissed the charges.

In 2017, Wikileaks document dumps sparked conversation about the Espionage Act, and the Congressional Research Service outlined the main uses of the law throughout American history, stating, “Historically, the Espionage Act and other relevant statutes have been used almost exclusively to prosecute (1) individuals with access to classified information (and a corresponding obligation to protect it) who make it available to foreign agents, and (2) foreign agents who obtain classified information unlawfully while present in the United States.”

The Obama Administration used the Espionage Act more than any other presidential administration, with federal criminal charges filed against eight whistleblowers, including Chelsea Manning and Edward Snowden.

The Trump investigation would represent the first time that someone who served as President has been the subject of an Espionage Act probe.

Write to Olivia B. Waxman at .

The Friday release of a previously sealed search warrant executed by the FBI at Donald Trump's Mar-a-Lago home this week reveals a startling aspect of the criminal investigation into the alleged mishandling of White House documents: the FBI was seeking evidence to determine whether the former president violated the Espionage Act and other laws related to national security.

Under a section labeled "property to be seized," the warrant, viewable here, indicates that the FBI agents were seeking "all physical documents and records constituting evidence, contraband, fruits of crime, or other items illegally possessed in violation of" three sections — 2071, 1519 or 793, better known as the Espionage Act — in Title 18 of the United States Code.

A receipt that accompanied the unsealed warrant shows what federal agents collected in their search of Trump's Palm Beach, Fla., residence.

Among the materials retrieved were 11 sets of classified documents, including some marked "top secret" that are only meant to be viewed at secure government facilities.

Binders of photos, a handwritten note, unspecified information about French President Emmanuel Macron and an executive grant of clemency for former Trump aide Roger Stone were also listed on the receipt.

That those items were part of an investigation into potential crimes associated with violations of the Espionage Act is historic. No U.S. president has been investigated for violating the act, which was first enacted by Congress in 1917 during World War I.

Three sections of Title 18 of the United States Code are listed on the warrant. Section 793 covers the unlawful retention of defense-related information that could harm the United States or aid a foreign adversary. Section 1519 covers destroying or concealing documents to obstruct government investigations or administrative proceedings. Section 2071 covers the unlawful removal of government records.

Trump claimed on Friday that he declassified all the documents found during the search of Mar-a-Lago, The New York Times reports, noting elsewhere, however, that the laws listed on the warrant don't hang on whether the information was deemed unclassified.

Certain criminal laws enacted by Congress to protect national-security information are separate from the system of classifying documents with executive orders as "confidential," "secret" or "top secret," the Times report explains.

U.S. Attorney General Merrick Garland announced Thursday that, in an effort to be transparent, the Department of Justice filed a motion in a Florida court to unseal a search warrant the FBI executed at Donald Trump's Mar-a-Lago home earlier this week.

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The former president also "encouraged" the release of the warrant that was used to grant federal agents access to his Palm Beach, Fla., home, where they searched for classified nuclear documents and other materials, The Washington Post reported Thursday.

But before the warrant was released through official channels, it was leaked Friday afternoon when several news outlets published its contents.

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