What is the connection between what happened at the battle of puebla and the american civil war?

 France's goal was to help break up the American Union, at the time in the midst of a civil war, by helping the southern Confederacy: "The Mexicans had won a great victory that kept Napoleon III from supplying the confederate rebels for another year, allowing the United States to build a powerful army. This grand army smashed the Confederates at Gettysburg just 14 months after the battle of Puebla, essentially ending the Civil War."