Andrew Johnson vetoed a bill that gave reparations to formerly enslaved people, hence this phrase for an unfulfilled promise

Forty Acres and a Mule was a promise made during the Civil War by Union General William Tecumseh Sherman, who issued Special Field Orders No. 15, stipulating that freed slave families should be given forty acres of tillable land on the islands and coastal region of Georgia.

The phrase “Forty Acres and a Mule” has since become symbolic of unfulfilled promises to African Americans. Andrew Johnson, who became president after the assassination of Abraham Lincoln, overturned this order, returning the land to its previous Confederate owners. His actions effectively vetoed any potential reparations at the time for the formerly enslaved.