There are branches that are dedicated purely to reconnaissance and reclaiming individuals even if they were KIA and buried long ago.
If they are an American citizen and have deserted their post, etc, they should be brought home and this analyzed and decided based on interviews, investigation, trial - whatever. It's up to us to keep rule over our own people, it's not up to them.
If injustice is suspected then we must apply our own law.
Of course, hankering to do so is sort of at the bottom of the concern list - and in regard to Berghdahl, I have a feeling there's much more to 'the deal' that a cut and dry 5 for 1. I'm curious as to what in the hell he told them - and whether or nto someone like that should remain in foreign possession is really what should be discussed.