I appreciate the well-reasoned reply, Shellhead, but must say that we disagree on several points.
First, I think Bowen Marsh's tearful declaration of "for the Watch" has misled many to believe that he acts out of an honorable intent to preserve the institution he's dedicated his life to in the face of Jon's oathbreaking. Setting aside the question of whether political neutrality is a sworn mandate of the Night's Watch at all--as opposed to a convention based on interpretations of the vows and practical concerns such as reassuring the nobility that the once tens of thousands of armed men on the Wall are no threat--this characterization of Marsh as a selfless hero, almost a martyr, runs counter to everything that's known about him. I'm not sure if you read my essay but, in Part 2, I discuss how Marsh's objections to Jon's dealings with Stannis are likely based less on upholding the NW's traditional noninterference and more on his fear of reprisal by the Lannisters' proxies in the North, the Boltons, should the NW be implicated in Stannis's treason against the Iron Throne. Marsh's advice to Jon is not "take no part" but "side with the winners," who he feels will not be Stannis and allies.
Additionally, Marsh is immovably prejudiced against the wildlings, to the point where he makes patently ridiculous suggestions that amount to strategic suicide. The notion that it'd be perfectly fine to leave the wildlings to die beyond the Wall, for instance. Which not only ignores the fact that more dead means more wights but also that the more belligerent wildlings, like Tormund and the Weeper, would never crawl back to their villages in defeat when they can mass again for do-or-die attacks on the Wall. Marsh is no great shakes as a military commander, anyways, as evidenced by his ASOS performance that costs the NW a hundred men. By ADWD, he's inflexible and averse to any kind of risk, refusing to countenance even hunting parties in the Haunted Forest when this is an obvious solution to the food shortage he bemoans.
In short, Jon's absolutely right not to heed much of Marsh's so-called counsel, IMO. Being Lord Commander doesn't mean you're obligated to implement the bad ideas of your subordinates. Your subordinates, however, are obligated to obey your orders and without questions.
Second, so far as we readers know, Marsh heads a grand conspiracy of four men, counting him. Marsh's accomplices are probably sitting with him in the Shieldhall: Wick Whittlestick (confirmed), Left Hand Lew, and Alf of Runnymudd. The first two are stewards and the last, a builder who perhaps nurses a personal grudge against Jon over the death of a friend, Garth Greyfeather, at the hands of the Weeper (Melisandre, ADWD).
From Jon IV, the NW is pretty evenly divided on Marsh's proposal that the gates be sealed, with the rangers mostly siding against. There's not much information afterwards on what the rank and file think of Jon's decisions, but I believe there are indications that Jon's well respected by his men. For starters, he personally interacts with them every day.
Jon donned his cloak and strode outside. He made the rounds of Castle Black each day, visiting the men on watch and hearing their reports firsthand, watching Ulmer and his charges at the archery butts, talking with kingsmen and queensmen alike, walking the ice atop the Wall to have a look at the forest. Ghost padded after him, a white shadow at his side. (Jon II, ADWD)
In Jon VII, the six recruits all choose to take their vows before the weirwoods, despite half coming from regions that don't worship the old gods. Why? My guess is that the younger men rather admire Jon, who's closer to their age and regularly trains with them.
Quite a few of the points you mention as negatives I see as lending Jon a certain charisma. He's the Bastard of Winterfell, raised in a castle with the trueborn Starks, who are still highly esteemed in the North. He risks his life to spy on the wildlings at Qhorin Halfhand's behest, bedding a spearwife (star-crossed lovers!), but ultimately stays true to his vows, taking command of the undermanned Wall against Mance Rayder. And Ghost? Scary, true, but also really, really cool. Especially with Mormont's raven perched on Jon's shoulder and Longclaw--which I remind you Jon wins by saving the Old Bear's life from the first wight seen south of the Wall in some eight thousand years--strapped across his back. Even Jon's dealings with Stannis and the wildlings reinforce the perception of his power. He's a man who treats equally with kings and, as the wildlings pass the Wall, the clan chiefs offer him tribute one after another.
Marsh may claim that he represents the men's interests, but the one time a crowd of black brothers actually approaches Jon with concerns, in Jon XI after his negotiations with Tormund, Marsh is nowhere to be seen. It's Ulmer of the Kingswood, a survivor of the Fist of the First Men, who comes forward to speak for the rest, and he asks whether it'll be peace or blood and iron with the wildlings. Keep in mind that the NW will bleed, too, if Tormund chooses to fight.
Granted, Othell Yarwyck and Septon Cellador support Marsh. Yarwyck's particularly susceptible to peer pressure, however. In ASOS, Alliser Thorne, with Marsh at his side, presses Yarwyck into withdrawing his candidacy as Lord Commander in favor of Janos Slynt but, as soon as Yarwyck senses that Jon might prove the winner, he swings his vote to Jon. I bet Yarwyck loses his nerve to oppose Jon after facing a Shieldhall packed with wildlings clamoring to fight for Jon. As for Septon Cellador, everyone knows he's a useless lush. Possibly his most memorable moment in the series prior to ADWD is Donal Noye threatening to toss him off the Wall during Mance Rayder's initial attacks.
Bottom line, that Marsh and his accomplices act against Jon by no means shows that the entire Night's Watch is opposed to Jon's policies.
Except that, once Tormund's people are south of the Wall, the black brothers have opportunity to observe the wildlings at close range, too--their warriors, yes, but also their women and children, old and wounded and infirm. And, despite Marsh's dire predictions that the wildlings will betray the NW, nothing of the sort happens. Instead, the free folk obey Jon's orders, manning castles along the Wall in preparation for warring with the Others.
Originally Posted by Shellhead
Regarding this, by ADWD, there's no excuse for ignorance as to the threat of the Others on the part of any man of the NW who isn't an idiot, like Owen the Oaf, or willfully blind, like Marsh. Undead Othor and Jafer Flowers infiltrate Castle Black in AGOT to assassinate Lord Commander Mormont, killing the acting First Ranger and five others in the process. Near three hundred men are lost on Mormont's ranging, a third of the NW's strength, and most to the wights at the Fist of the First Men. It's not as if there are no survivors either, which might've left the NW puzzled as to who the enemy is.
Furthermore, exactly what else besides the conquest of Westeros would the Others be interested in? It's been thousands of years since the last Long Night, but all the North's oral and written histories agree that the Others are hostile and the NW's purpose is to fight them. Pretty much everything about the Others that's known to us readers is known to the NW, and the exceptions would tend to suggest the Wall is more vulnerable, not less so. From Coldhands being unable to cross the Wall and Bran's chapters in general, people have speculated that the Wall's magically warded against the Others and wights. Jon has no access to such intelligence, though, as Sam's sworn to secrecy about Bran and his companions. The Wall's just another static fortification to him, impressive but dependent on the mettle of its defenders, who currently aren't much to speak of in number or quality. Plus, with all the rumors of Joramun's horn, Jon can't rule out the Others having magical means to bypass the Wall. A potential danger that should be obvious, anyways, seeing as the Others are necromancers!
Jon even gives a speech about the NW and wildlings making common cause against the Others in Mole's Town. A dozen spearmen and a dozen archers are there to hear it, along with Bowen Marsh.
"The Wall protects the realm... and you now. You know the foe we face. You know what's coming down on us. Some of you have faced them before. Wights and white walkers, dead things with blue eyes and black hands. I've seen them, too, fought them, sent one to hell. They kill, then they send your dead against you. The giants were not able to stand against them nor you Thenns, the ice river clans, the Hornfoots, the free folk... and as the days grow shorter and the nights colder, they are growing stronger. You left your homes and came south in your hundreds and your thousands... Why, but to escape them? To be safe. Well, it's the Wall that keeps you safe. It's us that keeps you safe, the black crows you despise. [...] A wall is only as good as the men defending it. [...] No one is asking you to take our vows, and I do not care what gods you worship. My own gods are the old gods, the gods of the North, but you can keep the red god or the Seven or any other god who hears your prayers. It's spears we need. Bows. Eyes along the Wall." (Jon V, ADWD)
I'm not sure how much clearer Jon can get. Another Long Night is imminent. Marsh is a coward in denial.