Is Samwell Tarly a deserter of the Night's Watch?

Question

In Game of Thrones season 5 episode 10, Jon sends Samwell Tarly to the Citadel in Oldtown to train as a maester so as to become maester Aemon's successor.

In season 7 episode 5, Sam decides to leave Oldtown, apparently without finishing his training; in season 7 episode 7, he ends up in Winterfell.

Since Sam has (1) neither finished his training, (2) nor mentions going back to Castle Black, should Jon, as King of the North, treat him as a deserter of the Night's Watch and behead him, like Eddard Stark beheaded Will in season 1 episode 1?

Update 1: Since some people claim that Sam's primary task is to learn about the White Walkers, I would like to point out the following:

• In season 5 episode 10, Sam says to Jon, "Send me, Gilly and the baby to Oldtown so I can become a maester. That's what I'm meant to be, not this." He then adds, "I'd be more use to you as a maester. More use to everyone now measter Aemon's gone. The Citadel has the world's greatest library. I'll learn about history, strategy, healing, and other things, things that will help - when they come." Dragonglass and Valyrian steel are mentioned just before these words are spoken but they are not stated as reasons for going to the Citadel.
• When he arrives at the Citadel, Sam says, "I am to be the new maester." Quitting before the end of his training means he does not fulfil part of his task.

Update 2: Since some people correctly pointed out that Winterfell is on the way to Castle Black, I'd like to point out what Sam says to Bran when Bran asks why he came to Winterfell: "Jon is the one to lead the fight against the dead. I know he is. And he can't do it alone. So I've come here to help him." This at least suggests that he wants to stay at Winterfell, rather than travelling back to Castle Black.

Answer 1

Sam hasn't Deserted.

His primary job when going to the Citadel was to learn about the White Walkers/wights and Dragonglass and things that will help the watch.

I'll learn about history, strategy, healing. And other things, things that will help when-- when they come.

It only appears to be secondary to become a Maester and Sam only leaves the Citadel when he realises they are dragging their feet and he'd actually be more use at the wall/with Jon.

Per the question update Jon only agrees to let Sam go when he says he will learn about "other things". He doesn't want him to go when he says he wants to be a Maester so his task was never really to become a Maester.

When Sam comes back to Winterfell we only see him briefly arriving and then talking to Bran. So for all we know, it is just a pit stop on his way back to the North. However, note that Sam will know Jon is now back in Winterfell, as he sent a raven to him there, so it makes sense for him to go there to pass on information too.

Also, though I can't see it clearly, it looks like Sam is wearing black in the scene when he talks to Bran.

Lastly, Sam is perhaps Jon's closest friend and Jon needs Sam for his information so even if Sam was a deserter he would most likely pardon him anyway.

As @Flater says in the comments:

There's also a reasonable argument to be made that the White Walker threat surpasses anything else, so Sam would not be punished regardless of Jon and Sam being friends. Similar to how you won't necessarily get a speeding fine if you drive a bleeding man to the hospital (or more broadly, why service vehicles get to circumvent traffic laws during an emergency).

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People have claimed that Sam has deserted because he's stated that he is going to help Jon in the fight against the dead instead of going to the Wall. First off Jon has the larger army and I think it's clear he'll be going back up North so it doesn't really stand. However, I'd also like to include the Night's Watch oath where it pretty much says one of their main tasks is guarding against the cold.

Night gathers, and now my watch begins. It shall not end until my death. I shall take no wife, hold no lands, father no children. I shall wear no crowns and win no glory. I shall live and die at my post. I am the sword in the darkness. I am the watcher on the walls. I am the fire that burns against the cold, the light that brings the dawn, the horn that wakes the sleepers, the shield that guards the realms of men. I pledge my life and honor to the Night's Watch, for this night and all the nights to come.

Answer 2

There are already some great answers focusing on Sam's specific actions and Jon's specific orders. I think we're missing a key point, here.

There's a big difference between desertion and going AWOL, and this difference is acknowledged in many modern militaries.

In military terminology, desertion is the abandonment of a duty or post without permission (a pass, liberty or leave) and is done with the intention of not returning.

In contrast, unauthorized absence (UA) or absence without leave (U.S.: AWOL; British & Commonwealth: AWL) refers to a temporary absence. very reliable source ;)

Furthermore, desertion often is defined by intent - was Sam 'trying to avoid hazardous duty' or 'shirk contractual obligation'? No. If anything, he has just abandoned the safest location in Westeros to go to the most dangerous with the intent of fulfilling his primary obligation, which is to defend the living.

Now yes, since Sam was on assignment (however strictly or loosely worded by the Lord Commander) to study to become a maester and left the Citadel without permission from the Night's Watch or forcible discharge by the maesters, he is technically AWOL.

However, since Sam is actively working to support the Night's Watch, is moving closer to the metaphorical sound of the guns, and for all we know intends to later go back to the Citadel to try and resume his studies, he is in no way deserting.

Answer 3

No. Samwell was sent by the Lord Commander (Jon Snow) to the Citadel to study to replace Maester Aemon. We already know from the first season that Nights Watchmen may be sent south like this, as Yoren is sent to recruit from all over Westeros.

The last time we see Samwell he has returned to Winterfell and is seeking out Jon:

Jon's the one to lead the fight against the dead, I know he is. But he can't do it alone, so I've come here to help him.

Samwell has not deserted, but in fact appears to be carrying out his duty.

As for abandoning his studies, I don't see how returning to the Wall could be considered desertion. Sam was given permission to go to Old Town, rather than being ordered to go there and stay until he became a maester. When Sam asks Jon to let him go there, he specifically says he wants to learn about the Walkers:

JON: I need you here, Sam. If you leave, who's left to give me advice I trust?

SAM: Well, there's Edd. I'd be more use to you as a maester. More use to everyone now that Maester Aemon is gone. The Citadel has the world's greatest library. I'll learn about history, strategy, healing. And other things, things that will help when - when they come.

Sam is doing exactly what he said he would. He has learned about the Walkers, the Walkers are coming, and he is attempting to make what he learned useful in the fight against them.

Answer 4

He didn't sail off to the Summer Isles. He's returning to the North to help defend the wall. He's done nothing to indicate that he is a deserter.

Gilly and the boy are problems, as is the fact that he stole his father's sword. Abandoning his Maester training is really the least of Sam's offenses.

Answer 5

He deserted the Nights Watch, because he left the citadel without becoming a Maester and never returned to Castle Black. He also knew Jon was no longer even a part of Nights Watch. He deserted them.