Waiting where for almost 400 years? The United States became a declared political entity in 1776, although that remained in dispute for some time after that, as far as the British were concerned. It wasn't until the Treaty of Ghent (Christmas Eve, 1814) that the British stopped contesting that. Incidentally, that also committed to ending slavery.
Using 1788 as the mark, when the Constitution was ratified, there were 77 years that slavery was an institution in the United States, ending in 1865 (the slaves in MD who had not already been manumitted were finally freed at the end of the war, immune to the Emancipation Proclamation, because technically, Maryland was not a 'State in rebellion').
I have purposefully not included the Colonial period, because the government in the colonies was either the English Monarchy, The French Monarchy, or the Spanish Monarchy or their various agents and governors.
So, please. After thousands of years of slavery in Africa, the trade became a means for those in Africa to obtain goods not available there, get rid of dead weight in their tribe, or enrich themselves through the sale of captives. Someone sold those people to the slavers, and only a very small fraction (some 4%) of the African Slave Trade was destined for the United States.
The rest went elsewhere.
