The main way in which <span>settlement of the west increase tension between the north and south was that each new state in the Union had to decide whether to be "slave" or "free"--leading to much more tension over the issue of slavery. This tension eventually led to the Civil War. </span>
because cotton was the main source of income for the southern economy so they will give this cotton to the north to export it that why there was a phrase called cotton is king
