That's a lot of questions! You need not give me the "brainliest," as I may only respond to a couple of those points for the sake of time here.
#2 in your list: In Lincoln's first inaugural address, he said: "Plainly, the central idea of secession is the essence of anarchy." In other words, if states could choose to secede from the union, then there was really no union and no government. (Anarchy is the absence of government.) Only if we abide by the constitutional checks we place on ourselves in a democratic republic are we exercising genuine government. Otherwise, we fall into chaos or some sort of dictatorial state. Lincoln felt that the whole concept of self-government was at stake, threatened by the South's desire to secede. Lincoln had to treat the secession of several states as an act of rebellion.
#5 in your list (closely related to #2): The states that had seceded already had caused the civil war, in Lincoln's estimation. The northern states had to respond to hold the union together. The southern states claimed to be afraid for their property, peace and safety with an administration like Lincoln's in charge. But Lincoln saw those fears as unfounded, that all states would continue to enjoy their constitutional privileges. But seceding from the union cut them off from all stability and security.
Germany's resumption of submarine attacks on passenger and merchant ships in 1917 became the primary motivation behind Wilson's decision to lead the United States into World War I.
