Please help asap! Why wasn't the Missouri compromise of 1820 enough to end tension between the north and south by the 1840s?

a. All of Texas would be a slave state, which went against the Missouri compromise.
b. Some new territories went both above and below the line of compromise.
c. Mexico had outlawed slavery, so the new land gained from them could not allow slavery.
d. The North and South continued to fight over territory by the Rio Grande.

under god i have placed my chiest strentgh and the safe guard to my loyal subjects

it was certainly a debatable decision, mainly because it was based primarily on political - and not on legal or social - views. since the congress at that time was led by members of the republican party, and the territory that the tribes wanted to turn into an exclusively indian state was predominantly democratic, the proposal (as expressed in the constitution) did not succeed, but the constitution itself proved to be of crucial importance in the creation of the state of oklahoma, and, most importantly, it guaranteed the involvement of representatives of the indian tribes in the government of the future joint state.  

as a member of congress, i would have voted to ratify the constitution, or at least to have it tabled. ignoring it was an interested and partial decision.