Well assuming you mean America, and not considering Civil War, I would say the draft of the Constitution Thomas Jefferson want to make slavery illegal, but he needed the southern states approval.
it did not want the U.S. to be involved in international politics.
There also people that think WW1 was the first modern war.
But the reason for people to believe that the fist modern war was the civil war is because it was the first war after the industrial revolution, that also meant more technology and advancement were made, and last it was because these new technology's resulted in more deaths than any other American war.
#3 is Earth's orbit causes the seasons because when the northern hemisphere is facing away or being deprived of sunlight it is winter. Same for everything else
