Answer:
They would destroy Paris
Explanation:
Following the commencement of the French Revolution in Paris, France in 1789. The Prussian government under the command of Field Marshal Gebhard Leberecht von Blücher threatened to destroy Paris if and when the royal families are harmed.
This declaration eventually aggravated the anger of the masses, as they immediately murdered the royal guards and imprisoned King Louis, Marie Antoinette, and their children
Men were needed to work in war-related industries in the North. Most white men were being drafted, while draft boards were so racist that blacks tended to be excluded, and available to fill the industrial jobs.
He was thinking it would have crippled the Union Army.