'If British diplomats and strategic thinkers had been more strongly committed to this idea, a very alternative outcome is easy to imagine'
What if the British had not returned this territory at the end of the war? That could potentially sour the Anglo-American relationship some, but it's not like all of Maine was taken, just some more tracts of snow. Canada gets to extend somewhat more south than it did historically. And we would have New Ireland next to New England, how fun. What would this region be like, this additional Maritime Province?