Lincoln had to hold his truncated Union together in the face of the sacrifices it would now have to make. That meant retaining the allegiance of Missouri, Kentucky, Maryland, and Delaware, four loyal states where slavery was legal. Lose them, the president acknowledged, and “[w]e would as well consent to separation at once, including the surrender of this capitol.” Or, as he’s said to have added: he “wanted God on his side, but he must have Kentucky.”
