One of the principles is that only the congress can pass laws regarding taxes and can collect taxes for the country. This principle is important because it prevented anyone else who might became a wealthy corrupt politician from collecting taxes from people in the state where he was the most powerful person. It also prevents individual states from exploiting people.
Generally speaking, from the 1830s on, people hoping to settle in the Northwest "B-traveled along the Oregon Trail," since this had become a well-established route.
