Whistleblower advocates are calling on President Donald Trump to pardon former National Security Agency contractor Reality Winner, who was sentenced Thursday to over five years in prison for performing a "public service."

"I think what has been done by the Trump administration to Reality is just terrible, and it's one of the worst miscarriages of justice I've seen in a long time."

—James Risen, The InterceptWinner, who was prosecuted under the Espionage Act, accepted a plea deal that sends her to prison for 63 months for leaking to the press in 2017 information that exposed a Russian cyberattack against U.S. voting systems. It's the longest sentence ever in federal court for leaking government information to the press.

Seizing upon Trump's characterization of the sentence as "unfair," some of Winner's advocates, including her mother, responded to the president's tweet by saying he should exercise his authority to pardon her.

"I think what has been done by the Trump administration to Reality is just terrible, and it's one of the worst miscarriages of justice I've seen in a long time," said James Risen, The Intercept's senior national security correspondent, to Democracy Now! on Friday. "What Reality Winner did was a public service," he said.

"The disclosure of the document in this, that The Intercept published, ... provided a really important wake-up call to the American people that ... Russian intelligence was hacking into the election systems of states. And the Senate Judiciary Committee, in a report earlier this year, wrote that the Homeland Security Department had failed to adequately warn state election officials about the Russian hacking threat, and said ... it was only because of press disclosures that state officials began to be alerted to the Russian threat, cyberthreat, which shows that even Congress recognizes that what Reality Winner did was a public service," Risen said.

In a statement issued Friday, Reporters Without Borders (RSF) also condemned the sentence.

"Reality Winner's outrageous sentence is a clear threat to investigative journalism, freedom of information, and the public's right to know, as it could have a chilling effect on sources," said Margaux Ewen, RSF's North America bureau director.

"We are concerned that her sentence is just the beginning of an intense crackdown on whistleblowers led by Attorney General Jeff Sessions, who threatened last year to stifle leaks with harsh federal punishment. Winner's sentence shows that his threats are coming to fruition," she added.