How did the outcome of the mexican-american war, which added new lands to america, increase sectional tensions throughout the 1850s?

The Mexican-American War, added new lands to America creating increase sectional tensions throughout the 1850s as a divide between or an imbalance of enslaved states.  

Explanation:

The main question became should slavery be allowed in newly acquired territory.  This issue of the expansion of slavery led to the divide of the North and the South (eventually the Civil War).