Columbia subject headings:
Secession.
Southern States--Politics and government--1775-1865.
United States--History--Civil War, 1861-1865--Causes.
United States--Politics and government--1815-1861.
Harvard subject headings:
Secession
Southern States--Politics and government--1775-1865
United States--History--Civil War, 1861-1865--Causes
United States--Politics and government--1815-1861
Princeton subject headings:
Secession.
Southern States--Politics and government--1775-1865.
United States--History--Civil War, 1861-1865--Causes.
United States--Politics and government--1815-1861.