Defence argues charges in WikiLeaks case should be thrown out in legal motion accusing US of deliberately dragging its feet

The military court that is handling the prosecution of the WikiLeaks source Bradley Manning is likely to rule this week on whether the drawn-out nature of his court martial is in breach of his rights to a prompt trial.

The latest Bradley Manning pre-trial hearing at Fort Meade in Maryland that starts on Tuesday will focus on a "speedy trial" motion brought by the defence. It argues that the legal build-up to his eventual court martial has been so agonisingly slow that the defendant's basic rights have been violated.

Last weekend, Manning, who was arrested in May 2010 at the US army base outside Baghdad where he was working as an intelligence analyst, entered his 1,000th day in detention without trial. The moment was marked by scores of demonstrations around the world.

Military personnel are afforded similar protection against excessive delays before trial as are civilians. Under Article 10 of the Uniform Code of Military Justice, the US government is required to use "reasonable diligence" in proceeding to trial for anyone held in pre-trial confinement.

But in legal argument to the court prepared by Manning's main lawyer, David Coombs, the government is accused of deliberately dragging its feet.

"The government's behavior is nothing short of shameful," Coombs writes. He points out that it took 530 days to elicit classification reviews of sensitive material from different government departments.

"These classification reviews were not Tolstoy novels – they were generally documents that spanned three or four pages. Under no stretch of the imagination can a 530 day lag in completing a three or four page classification review be characterized as reasonably diligent," the defence lawyer wrote, adding: "530 days spent languishing in a brig is a very long time."

The Rules for Courts Martial (RCM) 707 states that under normal circumstances the accused should be brought to trial within 120 days of charges having been brought. With the start of the court martial now pencilled in for 3 June – more than three years after Manning was arrested – the defence is calling for all charges against him to be thrown out because of the breach of his rights.

The prosecution has argued that the material under discussion – the hundreds of thousands of diplomatic cables and other confidential state documents that Manning has effectively admitted passing to WikiLeaks – is so sensitive and potentially damaging to national security that the legal process has been by necessity slower to advance than usual. The government has also pointed out that some of the delays in the trial process have come as a result of defence requests.

It will fall to the military judge, Colonel Denise Lind, to decide which side of the argument holds sway. She could agree with the government and dismiss the defence motion out of hand; or she could side with the defence and dismiss the charges, even theoretically allowing Manning to walk free, though few close observers expect such a dramatic outcome to happen.