Slavery, which had up to now received little public
attention, began to assume much greater importance as a national issue.
In the early years of the republic, when the Northern states were providing
for immediate or gradual emancipation of the slaves, many leaders had
supposed that slavery would die out. In 1786 George Washington wrote
that he devoutly wished some plan might be adopted "by which slavery
may be abolished by slow, sure and imperceptible degrees." Jefferson,
Madison and Monroe, all Virginians, and other leading Southern statesmen,
made similar statements. The Northwest Ordinance of 1787 had banned
slavery in the Northwest Territory. As late as 1808, when the international
slave trade was abolished, there were many Southerners who thought that
slavery would soon end. The expectation proved false, for during the
next generation, the South became solidly united behind the institution
of slavery as new economic factors made slavery far more profitable
than it had been before 1790.
Chief among these was the rise of a great cotton-growing
industry in the South, stimulated by the introduction of new types of
cotton and by Eli Whitney's invention in 1793 of the cotton gin, which
separated the seeds from cotton. At the same time, the Industrial Revolution,
which made textile manufacturing a large-scale operation, vastly increased
the demand for raw cotton. And the opening of new lands in the West
after 1812 greatly extended the area available for cotton cultivation.
Cotton culture moved rapidly from the Tidewater states on the East coast
through much of the lower South to the delta region of the Mississippi
and eventually to Texas.
Sugarcane, another labor-intensive crop, also contributed
to slavery's extension in the South. The rich, hot lands of southeastern
Louisiana proved ideal for growing sugarcane profitably. By 1830 the
state was supplying the nation with about half its sugar supply. Finally,
tobacco growers moved westward, taking slavery with them.
As the free society of the North and the slave society
of the South spread westward, it seemed politically expedient to maintain
a rough equality among the new states carved out of western territories.
In 1818, when Illinois was admitted to the Union, 10 states permitted
slavery and 11 states prohibited it; but balance was restored after
Alabama was admitted as a slave state. Population was growing faster
in the North, which permitted Northern states to have a clear majority
in the House of Representatives. However, equality between the North
and the South was maintained in the Senate.
In 1819 Missouri, which had 10,000 slaves, applied to
enter the Union. Northerners rallied to oppose Missouri's entry except
as a free state, and a storm of protest swept the country. For a time
Congress was deadlocked, but Henry Clay arranged the so-called Missouri
Compromise: Missouri was admitted as a slave state at the same time
Maine came in as a free state. In addition, Congress banned slavery
from the territory acquired by the Louisiana Purchase north of Missouri's
southern boundary. At the time, this provision appeared to be a victory
for the Southern states because it was thought unlikely that this "Great
American Desert" would ever be settled. The controversy was temporarily
resolved, but Thomas Jefferson wrote to a friend that "this momentous
question like a firebell in the night awakened me with terror. I considered
it at once as the knell of the Union."