Ow did the western expansion heighten sectional conflict between North and South

This is a module based on the book America: A narrative historypublished by the W W Norton & Company.
This is a narrative essay, focus on the the period around Louisiana Purchase, Westward Expansion and how did these events heighten sectional conflicts between North and South.
The requirements are:
Select a set of relevant primary sources (minimum of 3 documents from the Norton America Study Space Website)
documents.aspx

Select a relevant secondary sources (minimum of 3 books from the book guide, excluding the text book America: A narrative history
Suggested book list:
C. Wiltse, The New Nations 1800-1845
M. Smelser, The Democratic Republic 1801-1815
E. Pessen, Jacksonian America
G. Van Deusen, The Jacksonian Era 1828-1845
D. Miller, The Birth of Modern America 1820-1850
H.L. Watson, Liberty and Power: Politics of Jacksonian America
F. Merk, Manifest Destiny and Mission in American History
R. A. Billington, Westward Expansion
D. Potter, The Impending Crisis 1848-1861
B. Levine, Half Slave and Half Free: The Roots of Civil War