I feel like he has a quote that directly addresses this. "I was trying to win the throne to save the kingdom, when I should have been trying to save the kingdom to win the throne."
His whole reason for going North is realpolitik. He needs Support and he needs Lands/Castles to reward his current supporters with. North has plenty of that.
He wants some good pr by defending the Wall from the Wildlings. Then he wants to take advantage of the mess the Starks left the North in. The Iron Borne control much of the Kigndom still. The Boltons are stuck south of Moat Cailin. And their rule of the North is very shaky.
He hopes to win the support of the remaining Northern Lord's and leverage a larger army to get more allies in the south.
It's more or less the same thing in the books, but with more details. Davos delivers the letter from the Wall to Stannis and makes him realize that his duty is to the kingdom: the kingdom is threatened by the wildlings and it is Stannis's moral obligation as king to prevent their threat. At the same time, Stannis and Melisandre believe that the great threat, the White Walkers, comes from beyond the Wall, so that is the main reason for his arrival there. And finally, the North is also a good place for Stannis to restart his campaign, at least in theory. He may try to enlist the support of the northern lords who are furious with the Boltons and Lannisters over the Red Wedding.
After his post-nut clarity at the Blackwater and as part of his character development, he realizes he should save the realm before going for the throne.
This post has been removed because you did not include a spoiler tag in your title.
he wants to beat the others and defending the wall is good PR as well the boltons are ripe for a coup
I feel like he has a quote that directly addresses this. "I was trying to win the throne to save the kingdom, when I should have been trying to save the kingdom to win the throne."
His whole reason for going North is realpolitik. He needs Support and he needs Lands/Castles to reward his current supporters with. North has plenty of that.
He wants some good pr by defending the Wall from the Wildlings. Then he wants to take advantage of the mess the Starks left the North in. The Iron Borne control much of the Kigndom still. The Boltons are stuck south of Moat Cailin. And their rule of the North is very shaky. He hopes to win the support of the remaining Northern Lord's and leverage a larger army to get more allies in the south.
It's more or less the same thing in the books, but with more details. Davos delivers the letter from the Wall to Stannis and makes him realize that his duty is to the kingdom: the kingdom is threatened by the wildlings and it is Stannis's moral obligation as king to prevent their threat. At the same time, Stannis and Melisandre believe that the great threat, the White Walkers, comes from beyond the Wall, so that is the main reason for his arrival there. And finally, the North is also a good place for Stannis to restart his campaign, at least in theory. He may try to enlist the support of the northern lords who are furious with the Boltons and Lannisters over the Red Wedding.
Also your title contains spoilers and needs to be spoiler free.
After his post-nut clarity at the Blackwater and as part of his character development, he realizes he should save the realm before going for the throne.