america places taxes on the american slave trade, almost doubling the cost of buying a single slave
the government profits raised by these new taxes are put into a rudimentary human rights program, which seasonally inspects slaves and their lodgings to assure they're in a sanitary environment and that they aren't being too badly abused (rotten shed = BAD whip lashes = BAD)
left over profits are put into purchasing slaves and freeing them
america also announces a slave-army program
if a slave owner allows their slave to join the slave army, they will get 80% of the slave's wages
the slave will get* the remaining 20%, and will be maintained by the government instead of the slave owner
if the slave is wounded badly enough in combat, they can leave the military as free men, with the money they gradually worked up doing their time in the military allowing them to find an acceptable living
* until they leave the military, the funds can only be used for the slave to buy themselves out of slavery to become free men on their own accord. the funds, of course, go to the ex-slave owner