A mistrial was declared in the court-martial of a US Army officer who publicly refused to fight in Iraq and criticised the war.
The military judge ruled that First Lt Ehren Watada had unknowingly signed a document that amounted to a confession of guilt.
Lt Watada (28) faced up to four years in prison on conviction of one charge of missing movements and two charges of conduct unbecoming an officer for his criticism of the war.
The mistrial was an unexpected ending to a case that had rallied the anti-war movement in the first known court-martial of a US Army officer for publicly refusing to serve in Iraq.
Lt Col John Head, the military judge, declared a mistrial after throwing out a "stipulation of fact" - an agreement over certain facts of the trial - that forced the government to request a mistrial instead of immediately arguing its entire case over to prove those facts with new witnesses.
The judge said he could not accept the stipulation, because it amounts to a confession to the missing movements charge when Lt Watada stated he is not guilty.
The accused's lawyer, Eric Seitz, said the mistrial was a "disastrous" outcome for the government because a retrial would constitute double jeopardy, which forbids a defendant from being tried twice for the same crime.
"These events today are going to be the death knell for the government's case," said Mr Seitz, who added that the government faces an uphill climb since it requested the mistrial.
Lt Col Robert Resnick, chief of administrative law at Fort Lewis, contended that double jeopardy had not attached and the government has the legal authority to retry the case.
Lt Watada's case rested on his assertion that he would not go to Iraq because he considered it an unlawful order that would make him party to war crimes and it was therefore not his duty to obey it.
The judge set the new trial to start in mid-March, but agreed the timing would be subject to change.