BOSTON — A federal judge on Tuesday sentenced a member of the Massachusetts Air National Guard to 15 years in prison after pleading guilty to leaking highly classified military documents about the war in Ukraine.

Jack Teixeira pleaded guilty earlier this year to six counts of withholding and intentionally transmitting national defense information under the Espionage Act following his arrest in the most high-profile national security case in years. He was arraigned in an orange jumpsuit and showed no visible reaction as he was sentenced by US District Judge Indira Talwani.

Earlier in the hearing, he apologized to the judge.

Prosecutors initially sought a 17-year sentence for Teixeira, saying he “committed one of the most significant and significant violations of the Espionage Act in American history.”

Defense lawyers asked for an 11-year sentence. In the sentencing memorandum, they acknowledged that their client “made a terrible decision that he repeated for 14 months,” but argued that Teixeira’s actions, while criminal, were never intended to “hurt United States”. He also had no criminal record.

The security breach raised alarm over America’s ability to protect its most closely guarded secrets and forced the Biden administration to try to contain the diplomatic and military fallout.

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Jack Teixeira, the Massachusetts Air National Guardsman who prosecutors said “committed one of the most significant and significant violations of the Espionage Act in American history,” is put to be condemned Tuesday in federal court in Boston.

He pleaded guilty in March on six counts of withholding and intentionally transmitting national defense information.

Prosecutors asked the judge to impose the maximum sentence of 200 months — more than 16 years — in prison.

“The harm the defendant caused to national security by the disclosure of national defense information is extraordinary,” prosecutors said in a brief filed before the sentencing hearing. “By posting intelligence products on the social media platform Discord to feed his own ego and impress his anonymous friends, Teixeira caused exceptionally serious damage to the national security of the United States. The scale of his betrayal is staggering.”

The defense asked for the minimum sentence, citing Teixeira’s autism and ADHD. They also claimed that they did not intend to harm the country, only to educate their online friends about world events.

“Jack is still essentially a kid — at least, a ‘young offender’ — who has his whole life ahead of him,” defense attorneys Michael Bachrach and Brandan Kelley. specified in a memorandum presented to the judge before sentencing. “At the age of 22, a 132-month prison sentence would give him more than enough time to grow and mature; informed both of his conduct and of his punishment’.

“With the support of his family and mental health treatment providers, Jack should have little trouble living a productive life in prison and upon his eventual release,” the memo continued.

Teixeira is also currently negotiating a disposition of his parallel but related military prosecution, the memo said.

According to the signed plea agreement filed in court, Teixeira agreed to plead guilty to all six counts of the indictment, charging him with withholding and intentionally transmitting national defense information. In exchange, prosecutors agreed not to charge him with additional charges under the Espionage Act.

Teixeira “accessed and printed hundreds of classified documents” and posted images of them on Discord before his arrest in April 2023, a prosecutor said during his plea hearing.

As part of his plea agreement, Teixeira must sit for a debrief with the Department of Defense and the Department of Justice and return any sensitive materials that may remain in his possession.

Federal prosecutors said Teixeira had no business dealing with classified information because his low-level job did not require it.

“The defendant’s job was to troubleshoot computer workstations,” Assistant United States Attorney Jason Casey said during a hearing in March.

Still, Casey said, Teixeira accessed “hundreds” of classified documents inside the secure facility where he worked and “intentionally removed classified documents and information despite his superiors’ urgings to stop.”

Teixeira admitted in court that he knew the documents were marked classified.

Without elaborating, federal prosecutors said Teixeira exposed information about the compromise by a foreign adversary of certain accounts belonging to a U.S. company and information about equipment the U.S. was sending to Ukraine, how it would be transferred and how it would be used at reception Prosecutors said he also posted material about troop movements in Ukraine, a plot by a foreign adversary to attack US forces abroad and Western deliveries of supplies to the Ukrainian battlefield.

Teixeira enlisted in the Air National Guard in 2019, according to his service record, and had a top-secret security clearance beginning in 2021, according to the Justice Department.

The Justice Department said it began posting classified documents online in January 2022.

Teixeira will also face a military court martial on charges of violating the Uniform Code of Military Justice, according to the US Air Force.

The US military reserves the right to separately prosecute a service member who has already been convicted in federal court.

The Associated Press contributed to this report.