Americans used the ideal of manifest destiny to expand westward by buying the Louisiana purchase, then buying California and New Mexico and Texas from Mexico. As people moved westward due to the gold rush, people settled in this land, and popular sovereignty allowed a certain number of people to establish a state.
There was a flaw that allowed Thomas Jefferson and Aron Burr to tie in the electoral collage.
Killed three people and injured at least 264
Polio affected his legs mostly he couldn't walk and he had to be put in a wheelchair so he could move around more. I don't know about his character but hopefully this helped a little.