Lincoln-Douglas debates of 1858 during Illinois senatorial campaign: The Lincoln-Douglas debates were a series of seven, where Douglas argued on the basis of his opposition to the Lecompton Constitution and depicted Lincoln as a radical abolitionist. Lincoln condemned Douglas for not taking a moral stand against slavery.
International influence, also they had just defeated Spain when they begun having imperial ambitions, therefore they may want to fill that gap
Https://en.m.wikipedia.org/wiki/Japanese_invasion_of_Manchuria