Sgt. Bowe Bergdahl could be prosecuted if he abandoned his post before his capture, a top-ranking military has said.
General Martin Dempsey wrote Sgt. Bowe Bergdahl, 28, “is innocent until proven guilty”.
But he said the Army would not dismiss “misconduct if it occurred”.
Meanwhile, President Barack Obama defended his decision to free five senior Taliban leaders to secure Sgt. Bowe Bergdahl’s release on Saturday after five years in Taliban captivity.
In Warsaw, Barack Obama said the US had a “pretty sacred rule” not to leave soldiers behind, arguing that the most important consideration was to bring home a young American held captive for five years.
“We don’t leave our men or women in uniform behind and that dates back to the earliest days,” Barack Obama said at a news conference.
“Regardless of the circumstances, whatever those circumstances may turn out to be, we still get an American soldier back if he’s held in captivity. Period. Full stop. We don’t condition that.”
Since Sgt. Bowe Bergdahl’s release on Saturday, a growing chorus of opposition Republicans have criticized the president’s decision to order the prisoner swap.
They have attacked the president for undertaking what they describe as negotiations with terrorists, and say the transfer of five Taliban senior prisoners from the detention facility at Guantanamo Bay, Cuba, to Qatar, puts Americans at risk.
And some have accused the president of contravening a law requiring the White House to notify Congress 30 days in advance of any transfers of prisoners from Guantanamo.
In Poland, Barack Obama said his administration had consulted Congress “for some time” about the possibility of a prisoner exchange, though he acknowledged Congress was not briefed ahead of time on the operation.
“We saw an opportunity, we were concerned about Sgt Bergdahl’s health… and we seized that opportunity,” he said.
On his Facebook page, Gen. Martin Dempsey, chairman of the joint chiefs of staff, wrote the operation was “likely the last, best opportunity to free him”.
“As for the circumstances of his capture, when he is able to provide them, we’ll learn the facts,” he wrote.
“Like any American, he is innocent until proven guilty. Our Army’s leaders will not look away from misconduct if it occurred. In the meantime, we will continue to care for him and his family.”
Sgt. Bowe Bergdahl of Idaho is in stable condition in a military hospital in Germany.
He went missing from a remote base in Paktika Province, Afghanistan, in June 2009. After mounting an intensive effort to locate and rescue him, the Pentagon concluded Bowe Bergdahl had intentionally abandoned his post before his capture, US media have reported. Efforts to win his release moved from the field to the negotiating table.
Since Sgt. Bowe Bergdahl’s rescue, the reaction from Republicans has grown increasingly hostile.
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