Updated

Legislation that would award the injured from the 2009 Fort Hood shooting the Purple Heart would adversely affect the trial of Maj. Nidal Hasan by labeling the attack terrorism, according to a Defense Department document obtained by Fox News.

The document comes following calls from survivors and their families for the military honor, because they say Fort Hood was turned into a battlefield when Hasan opened fire during the November 2009 attack. Fox News is told that the DOD “position paper” is being circulated specifically in response to the proposed legislation.

The document reads in part:

"Passage of this legislation could directly and indirectly influence potential court-martial panel members, witnesses, or the chain of command, all of whom exercise a critical role under the Uniform Code of Military Justice (UCMJ).  Defense counsel will argue that Major Hasan cannot receive a fair trial because a branch of government has indirectly declared that Major Hasan is a terrorist -- that he is criminally culpable."

A source with knowledge of the position paper told Fox News that DOD is putting on a full-court press by sending senior officials, including generals, to meet with lawmakers in an effort to block support.

But Neal Sher, counsel for the Fort Hood families involved in a federal lawsuit against the department, told Fox News that the document -- an "official Army response" to the request for Purple Heart status -- is "an utter outrage" and that it was not surprising given it comes from the same department which labeled the attack "workplace violence."

"This is a cynical travesty. What the government has done by making this statement is guarantee that anything done to help the victims will effectively prevent or impair Hasan's prosecution. There was no reason for the government to put this kind of a statement in writing, even if it were true (which it is not),"  Sher said via email.

Sher represents families who are suing the Defense Department over the shooting which killed 13 and injured dozens at the Texas Army base in 2009.

Fox News was the first to report in 2011 that DOD was handling the attack, in which survivors say the shooter shouted “Allahu Akbar” as he opened fire – in the context of workplace violence. Fox News was the first TV network, in June 2012, to interview the survivors.

The Defense Department document says that to expand the Purple Heart criteria to include “domestic criminal acts or domestic terror attacks would be a dramatic departure” from traditional criteria.

“The Army objects to (the proposal) because it would undermine the prosecution of Major Nidal Hasan by materially and directly compromising Major Hasan’s ability to receive a fair trial. This provision will be viewed as setting the stage for a formal declaration that Major Hasan is a terrorist, on what is now the eve of trial. Such a situation, prior to trial, would fundamentally compromise the fairness and due process of the pending trial,” the document said.

It continues: “Moreover, the effect of such an act by Congress would be to deprive the victims of these crimes the right to see justice done.”

But Sher said the Army's legal arguments that such a situation prior to a trial would fundamentally compromise fairness and due process are especially troubling given the Holder Justice Department wanted to prosecute the self-described architect of 9/11 Khalid Sheikh Mohammed and his four co-conspirators in a New York City federal court.

"Seriously? We could try KSM no problem, but helping out Hasan's victims creates due process problems?" Sher said.

Sher said the Fort Hood families he represents in the federal suit find it hurtful that DOD would now claim "such an unprecedented action would thwart the real and lasting measure that will bring closure to the grieving and harmed victims and families -- the trial itself."

While the document claims "the Government has vigilantly tended to the needs of the victims and families since the tragic events of November, 5 2009," Sher said the facts show the Army has failed to live up to its creed that no soldier will be left behind.

The Defense Department did not immediately return a request for comment from Fox News.