What effect did the American colonization society have on slavery?

The more telling question and its answer would be how did slavery affect the New World colonies of the European settlers. Initially the effect was prosperity.

Free self producing labor was efficient in the Americas for several hundred years.

The first slaves to arrive in the America were brought to Spanish colonies in South Carolina in the 16th century by Portuguese slave traders. Later the slave trade boomed in various New World colonies controlled by Spain, Great Britain and Portugal.

In what was later called the 13 American colonies, a Dutch slave ship brought African slaves to the British colony of Jamestown in 1619. By 1740, England had legalized slaveryand the slave trade in the 13 North American colonies.

Legalized slavery ended in the Western Hemisphere when Brazil abolished slavery in 1888.

While Great Britain controlled the 13 American colonies, the African slaves helped make the Southern plantations a source of wealth for Britain and her colonies.

With all of that said, the answer to how did American colonization affect slavery is a straight forward answer. The colonization of the Americas increased the demand for slavery.

Slavery in the new nation of the United States became an issue during the US Constitutional Convention. It was a dividing issue, as the Southern Colonies, soon to be the Southern States lobbied to keep slavery legal as it was under the British regime.

Opposition to this came from the colonies that were not dependent on slavery as a main source of wealth.

The compromise came to this: After 20 years, no more slaves could be imported into the new United States. Thus in 1808, Congress banned the importation of slaves.

This would dampen the demand for new slaves in the USA, but initially had no effect on the slave trade in other areas of the Americas. The demand for slaves in the West Indies, Brazil, and other parts of mostly the Southern Hemisphere continued.

Part of the reason was the high death rate of slaves in those areas. And plantations outside of the USA were huge in comparison to the ones in "Southern" States.

Northern States' economics had no "fit" in most places there but, and its a big But, the plantations in the "Southern" States were indeed a good match. Even when the importation of new slaves ended in 1808.

Sad to say, but the need for buying new slaves from the slave business traders, turned out to be a non-issue as the death rate in the USA was low compared to other areas in the Americas.

And the balance of male and female slaves were evenly matched. The shrewd plantation owners kept slave families intact and better treated so that by the time of the Civil War, the South was home to 3rd, 4th and even 5th generation slaves were among the 4 million slaves in the USA.

As it was seen, Northern anti slavery abolitionists, even people who were not radical anti slave citizens believed that slavery was wrong. The American colonization, in answer to the original question affected the ultimate abolishment of slavery in the USA.