The man who helped expose allegations Australian soldiers committed war crimes has lost an appeal and subsequently flagged pleading guilty to charges of leaking classified information.
Former military lawyer David McBride is facing five charges relating to providing classified information to journalists without permission.
The defence force documents led to news stories outlining potential war crimes committed by special forces troops in Afghanistan.
McBride was seeking to rely on an argument that his sworn defence force oath to "protect and serve" implied he could act in the public interest to disobey lawful military orders.
What constituted actions in the public interest was for a jury to decide, his lawyer Stephen Odgers argued.
While following orders was also in the public interest "there are situations that will arise where they need to contravene orders", he said.
ACT Supreme Court Justice David Mossop rejected the argument that a need to act in the public interest was indirectly contained within the oath.
Mr Odgers said the finding may cause significant public concern that defence personnel "must obey lawful orders, no matter how unreasonable or in breach of fundamental principles of justice they may be" or face criminal prosecution.
McBride's appeal of the decision was rejected by Chief Justice Lucy McCallum on Thursday.
"It is enough to say that His Honour's ruling on that issue is not obviously wrong," she said in her reasoning.
Prosecutor Trish McDonald argued that military personnel following orders was a foundational part of their service.
Disobeying orders due to what they thought was in the public interest would be "the antithesis of service", she said.
Chief Justice McCallum agreed there was "strong legal support" for the prosecution's case that discipline in the military "is of central importance".
She branded McBride's argument of a duty to act in the public interest under his oath as "an ambitious one".
Mr Odgers said his client may be forced to plead guilty after the argument he acted in the public interest in accordance with his oath was stripped away.
Justice Mossop is yet to determine whether the prosecution can withhold parts of the evidence for national security reasons.
McBride's team is fighting to have redacted versions of the documents unsealed for the jury, arguing it would hamper their case if the evidence wasn't presented.
Mr Odgers indicated they would push to halt the case if they lose this argument on the grounds it prejudiced the defence.
Justice Mossop is set to hand down his decision on Friday.
A jury is set to be empanelled on Monday. The trial was scheduled to run for three weeks.
