Manning, a former Army intelligence analyst who was known as Bradley Manning at the time she was prosecuted, was sentenced in a military court in August 2013 for leaking about half a million classified documents to the secret-spilling WikiLeaks site in 2010. Her attorneys have asked a military appellate court to dismiss her case or reduce her sentence to 10 years, which was the original sentence she sought at the time of her court-martial trial.

Manning's attorneys waited to file her appeal to the US Army Court of Criminal Appeals until yesterday, the deadline for submitting. So what took them so long to file?

Shortly after sentencing in 2013, Manning's trial attorney, David E. Coombs, had sought clemency for his client from the Army—a process that took months to conclude. The military rejected the request in April 2014, at which point the case was automatically referred to the appellate court.

But this wasn't the primary reason for the delay. The unprecedented case posed a number of difficulties for Manning's defense attorneys, says Vincent Ward, co-counsel for the Chelsea Manning Legal Defense team.