D. The right for people to decide for themselves (that's the "popular" part) without federal intervention.
For examples of how this didn't work as planned, see "Bleeding Kansas," Kansas-Nebraska Act, and much of the decade or so leading up to the start of the Civil War...
This is a biased question and should not be on this website. Try to not ask questions like this.
They were merged to the Iran soviet <span />
Preserve the union. He wanted to make sure the states stayed united as their intended purpose.