2 expanded after an episode with dragons and the north.
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I think Jon is being practical. Yes the dragons are great but the night king has magic and could easily blind them in clouds of snow. The army usually walks under a blinding blizzard so it isn't a sure thing.

Plus the biggest issue he has to deal with south of the wall is everyone killing each other off or worse attacking him from behind when they are trying to defend the wall. He has to unite everyone to stop the bloodshed.

Another thing to think about is that the night king may very well drag all those dead bodies back out of the ground to join his army once he is past the wall. The problem is no one knows how great the danger is so getting everyone ready and united is really the best option.

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After S07E06 we see exactly why the dragons aren't the perfect weapon verse them. I won't expand upon that but another thing I realized is that in that sea of undead, which includes giants and polar bears the actual white walkers are not going to be easy to see. The Night King and his group riding horses seem to just appear on the battlefield. They may remain hidden until they are ready to act.

I think Jon is being practical. Yes the dragons are great but the night king has magic and could easily blind them in clouds of snow. The army usually walks under a blinding blizzard so it isn't a sure thing.

Plus the biggest issue he has to deal with south of the wall is everyone killing each other off or worse attacking him from behind when they are trying to defend the wall. He has to unite everyone to stop the bloodshed.

Another thing to think about is that the night king may very well drag all those dead bodies back out of the ground to join his army once he is past the wall. The problem is no one knows how great the danger is so getting everyone ready and united is really the best option.

I think Jon is being practical. Yes the dragons are great but the night king has magic and could easily blind them in clouds of snow. The army usually walks under a blinding blizzard so it isn't a sure thing.

Plus the biggest issue he has to deal with south of the wall is everyone killing each other off or worse attacking him from behind when they are trying to defend the wall. He has to unite everyone to stop the bloodshed.

Another thing to think about is that the night king may very well drag all those dead bodies back out of the ground to join his army once he is past the wall. The problem is no one knows how great the danger is so getting everyone ready and united is really the best option.

--- edit ---

After S07E06 we see exactly why the dragons aren't the perfect weapon verse them. I won't expand upon that but another thing I realized is that in that sea of undead, which includes giants and polar bears the actual white walkers are not going to be easy to see. The Night King and his group riding horses seem to just appear on the battlefield. They may remain hidden until they are ready to act.

1
source | link

I think Jon is being practical. Yes the dragons are great but the night king has magic and could easily blind them in clouds of snow. The army usually walks under a blinding blizzard so it isn't a sure thing.

Plus the biggest issue he has to deal with south of the wall is everyone killing each other off or worse attacking him from behind when they are trying to defend the wall. He has to unite everyone to stop the bloodshed.

Another thing to think about is that the night king may very well drag all those dead bodies back out of the ground to join his army once he is past the wall. The problem is no one knows how great the danger is so getting everyone ready and united is really the best option.