The US Constitution
Politics 19th Century Style!
Each state is allocated "electoral votes" equal to the total number of Senators and Representatives allocated to that state.
In exchange for a prohibition on export taxes, the South agreed to allowing the slave trade to continue for just 20 more years, and for imported slaves to be taxable.
As a side note, the very day that the slave trade could constitutionally be prohibited, it was: on January 1, 1808.
Politics 19th Century Style