To those suggesting the photo is flipped - if you'll take a look at the bottom of the jacket you'll see the zipper is in the correct position. I spotted this looking for a way to prove or disprove the flipped photo suggestion.
A "possible" explanation is that he injured his right amr or shoulder, but with kerry, there is no way to tell why he'd do something like that. he might just be showing his real contempt for the military.
If he were caught off guard with a large piece of luggage in his right hand, would that make it excusable?