A group of veterans advocates wants to know why President Barack Obama commuted the sentence of Chelsea Manning and other felons but won't act on a pardon for thousands of veterans with post-traumatic stress disorder.

"We continue to hold out hope that President Obama, in his final days as commander-in-chief, will not forget the thousands of veterans with PTSD who have been denied access to health care and treatment from the Department of Veterans Affairs," Vietnam Veterans of America John Rowan said in a statement late Tuesday.

"As pardons are being issued to people who have been convicted of serious felonies, veterans who served their country in combat wait to be offered the same clemency."

On Tuesday, Obama commuted the sentences of 209 prisoners and issued 64 pardons in one of his final acts as president.

The majority of the decisions were for lower-level drug offenses, an issue that has been among Obama's top executive actions in recent years. But the list also included Manning, a former Army intelligence analyst sentenced to 35 years in prison for leaking sensitive information, and James Cartwright, a former Marine Corps general convicted of lying to the FBI about the release of sensitive intelligence information to reporters.

VVA officials have been pushing both Obama and President-elect Donald Trump to address the issue of "bad paper" discharges for troops who suffered from post-traumatic stress, traumatic brain injury, military sexual trauma or other mental health issues.

They estimate as many as 300,000 of veterans of the recent wars have been barred from receiving health benefits and other VA support programs because of unfair dismissals, which failed to take into account health problems related to military service.

Instead of being kicked out of the ranks for alcohol abuse, drug use and suicide attempts, those individuals should have received counseling or health services from the military, VVA officials argue.

Exactly how such a pardon for those veterans would work remains unclear. Because there is no standard list for what veterans would be eligible for a discharge upgrade, Obama’s staff would have to work out a deal with Trump’s staff to keep enrollment open for months or years.

That seems unlikely, given the few remaining hours of Obama’s presidency. Still, Rowan said he is hopeful White House officials will consider a last-minute action.

"We cannot wait another four or eight years for an outgoing president to take action to help the most vulnerable veterans in the country," he said.

Leo Shane III covers Congress, Veterans Affairs and the White House for Military Times. He can be reached at lshane@militarytimes.com.