Okay, so this has been floating around my head for a while.
What would happen if the United States decides not to purchase Alaska? It doesn't seem that far-fetched, perhaps Johnson is narrowly not impeached and the Senate refuses to ratify the purchase out of spite, or Seward has some sort of scandal which prevents him for effectively advocating for the purchase. Then, history continues much the same as in OTL; a change in possession of Alaska will probably not change all that much.
Then, in an alt-Russo-Japanese War (likely to happen, their spheres of influence would have collided regardless), Japan sends a small force to capture Alaska, and succeeds. Now, you have a Japanese colony, sparsely inhabited but with significant mineral and (later) oil reserves. What happens? How does this change the American perception of, and American relations with, Japan? British and Canadian relations?
What would happen if the United States decides not to purchase Alaska? It doesn't seem that far-fetched, perhaps Johnson is narrowly not impeached and the Senate refuses to ratify the purchase out of spite, or Seward has some sort of scandal which prevents him for effectively advocating for the purchase. Then, history continues much the same as in OTL; a change in possession of Alaska will probably not change all that much.
Then, in an alt-Russo-Japanese War (likely to happen, their spheres of influence would have collided regardless), Japan sends a small force to capture Alaska, and succeeds. Now, you have a Japanese colony, sparsely inhabited but with significant mineral and (later) oil reserves. What happens? How does this change the American perception of, and American relations with, Japan? British and Canadian relations?