France and the UK supported the Confederacy ‘cause they did business with the South. The South sold cotton in Europe and, with the proceeds, bought manufactured goods and shipped them back to the South.
Northern manufacturers didn’t like this. They wanted a a captive market for their goods in the South. With the control of Congress and the Presidency, the intended to impose a large tariff on imported manufactured goods.
That was the REAL basis for the Civil War.
Nice misdirection. The northern manufacturers & industrialists didn’t support the war. They were just as happy to sell to the southern slaveholders as a separate country as they were selling to them as fellow countrymen.
Of course, there was a little more of a ruckus raised over the Nebraska Territory & Bleeding Kansas, over the California & New Mexico territories, over John Brown & Gabriel & Nat Turner, over the House’s gag rule prohibiting debate on any anti-slavery issue, over over the Tanney court & their Dred Scott silliness, etc etc etc. It’s funny how even though the war wasn’t about slavery, every controversy that led to the war was always fundamentally about the two very basic question “should it be legal to own slaves?” and “should we change existing laws to make it illegal?”