Slavery existed a total of 78 years in the United States of America established with the signing of the Constitution.
Thomas Jefferson included strong anti-slavery trade language in the original draft of the Declaration of Independence, but other delegates removed it.
Sorry, the United States of Amercia became a nation with the signing of the Constitution in 1787.
Slavery existed in the US for sum total of 78 years.
What other country worked at an finally ended slavery over such a short timespan?
They need to start looking at Spain, Portugal, and other European countries, rather than the US.
In 1794 the US banned American ships from participating in the slave trade and the exporting of slaves from the US by foreign ships.
In 1800 the US banned its citizens from investment and employment in the slave trade.
In 1806 In a message to Congress, Thomas Jefferson calls for criminalizing the international slave trade, asking Congress to “withdraw the citizens of the United States from all further participation in those violations of human rights … which the morality, the reputation, and the best of our country have long been eager to proscribe.”
In 1808 in Michigan Judge Augustus Woodward denies the return of two slaves owned by a man in Windsor, Upper Canada. Woodward declares that any man “coming into this Territory is by law of the land a freeman.”
The slave trade was abolished by Great Britain in 1807 and by the US in 1808.
We fought a massive Civil War in the 1860’s to end slavery.
In 1866 Slavery abolished. US government treaties with the “Five Civilized Tribes” in the Indian Territory (the Cherokee Nation, Choctaw Nation, Chickasaw Nation, Muscogee Nation, and Seminole Nation), which allied with the Confederacy, required all five tribes to abolish slavery for renewed US recognition of their governments.
American Indians had not stopped the ownership of slaves Black or Indian.
So legal slave trading existed for 19 years in the US before it was outlawed.
Slavery continued until 1929 in Persia (Iran and other Muslim countries).
In fact forms of slavery are still practiced in the Middle East.
Nearly 50% of the world’s countries....
https://phys.org/news/2020-02-slavery-crime-countries-world.html
“In fact forms of slavery are still practiced in the Middle East.”
See Libya after Barack and Webb’s lover got done with it.