(Marvin Joseph/The Washington Post)

At the time, the Pentagon had invoked a rarely if ever used national security provision that stated it would harm the interests of the United States to inform Dullahan of the accusations against him. Ever since, the Vietnam veteran has been left wondering what it was that got him effectively blacklisted from the federal workforce more than two years ago.

Now he could finally find out. Maybe.

In one of his last acts before stepping down as secretary of defense, Robert M. Gates issued a letter granting an appeal by Dullahan, saying that he was “not convinced that procedures prescribed in other provisions of law that authorize your termination could not have been invoked in your case.”

“Therefore,” he wrote in the brief letter, “your appeal is granted.”

Exactly what that decision means, though, remains unclear, according to Dullahan’s attorney, Mark Zaid.

It could mean Dullahan gets to find out why he was terminated. It could mean he may ultimately get his job back. Or it could mean something else entirely.

Zaid said that “literally no one knows what this will do,” but described it as a “very significant development.”

“This is the [secretary] himself stepping back and saying that this could have been handled in a different way,” Zaid said.

The letter, which was first reported by Politico, isn’t going to have any immediate impact on Dullahan’s situation. There’s still some legal wrangling needed to determine exactly what Gates’s order means and what recourse Dullahan might have.

That could take some time — perhaps a few months. After all, it took two years for Dullahan to just get a response back from Gates.

Still, Zaid, his attorney, said it’s an unquestionably positive development from the view of his client.

“It fundamentally changes the landscape of the case,” he said.