A low-level airman, Teixeira pleaded guilty to sharing hundreds of classified files on the social media site Discord.

United States prosecutors will seek a 17-year prison term for an airman who admitted to leaking hundreds of highly classified military documents about the Ukraine war and other national security secrets.

In a sentencing memorandum filed earlier this week, prosecutors said the crime by Jack Teixeira, 22, a member of the Massachusetts Air National Guard, amounted to one of the most “consequential violations of the Espionage Act in American history”.

“The defendant took an oath to defend the United States and to protect its secrets — secrets that are vital to US national security and the physical safety of Americans serving overseas,” prosecutors wrote. “Teixeira violated his oath, almost every day, for over a year.”

The classified records were shared last year by Teixeira on the messaging app Discord. Authorities say Teixeira began by typing out copies that he then published online. Later, he photographed the files, some of which bore “SECRET” and “TOP SECRET” markings.

Mossad details

The leaked documents held highly classified information on allies and adversaries, with details ranging from troop movements in Ukraine to intelligence about Israel’s Mossad spy agency.

The breach embarrassed the Pentagon and forced the administration of President Joe Biden to scramble to try to contain the diplomatic and military fallout.

Unlike other leakers of US military secrets, Teixeira’s lawyers say he had no political goal and was not a spy working for a foreign government.

The lawyers are pushing for a lighter sentence of 11 years, saying their client, who pleaded guilty in March, “made a terrible decision” but never meant to harm the US.

“Instead, his intent was to educate his friends about world events to make certain they were not misled by misinformation,” said the lawyers. They also noted that Teixeira has autism and has never been convicted of a crime before.

“Jack has thoroughly accepted responsibility for the wrongfulness of his actions and stands ready to accept whatever punishment must now be imposed,” wrote Teixeira’s lawyers.

Prosecutors countered that Teixeira, who held a top-secret security clearance while working in cyberdefence operations, does not suffer from an intellectual disability that prevents him from knowing right from wrong. They argued that Teixeira’s post-arrest diagnosis as having “mild, high-functioning” autism “is of questionable relevance in these proceedings”.

“Whatever developmental or social difficulties Teixeira may have experienced, his decision to illegally disclose national defence information and put the lives of other people at risk was a volitional choice that he made knowingly, wilfully, and with full awareness of the consequences time and time again,” prosecutors wrote.

Teixeira, who is scheduled to be sentenced on November 12, cannot be charged with further Espionage Act violations under the terms of his guilty plea.