"and desertion coud have legal consequence. . . but that is the only thing he has done wrong in a legal sense."

Then he still has done something illegal. Period. As many posters have acknowledged there's the law...and then there's morality. I think it is morally wrong to assume another person's indentity, wether living or dead, without their permission. What gives Don either legal or moral superiority to live out the rest of the real Don Draper's life without his say so? Just because the guy's dead? Because his wife sort of gives him permission...she doesn't really have that right. Dick has Don's medals, that he also did not earn...that's fraudulent, too. I don't need a law degree to know that plenty of service people have been caught wearing medals they didn't earn, and it's not taken lightly.

How Dick/Don treats Don's widow is really immaterial. It doesn't change what he did/does.

He's disrespecting the dead...he even had a hand in accidentally killing the real Don Draper. He snuffs him out when he drops his lighter foolishly in some gasoline...and then just takes over his name.

Sorry, but he's morally guilty and legally guilty (at least of desertion, possibly fraud regarding accepting and wearing the medals, or whatever the military code of justice calls it). And he knows it.

"I have posted this thought about some legal perspective on Don's deception . . are any of the folks who have pontificated on the legal ramications of what Don did, um, laywers? I am a law school graduate. I am severely overeducated."

That's nice. Is your, um, specialty involving the Uniform Code of Military Justice (UCMJ)? Unless it is, you're pontificating a little here, too, because it's a whole different world from civilian law.