Excuse me, but exactly what machinery in 1860 would have replaced slaves and if tariffs depressed the price of cotton, why exactly was the price of cotton in 1860 at all time highs? In fact, the Confederate strategy to gain European recognition was a self-imposed cotton embargo which they diluded themselves into thinking would force England and France into recognizing them.
Did England and France impose duties on cotton?
Because the new protectionist tariff that would have killed the southern economy did not take effect until 1861.