[GOPcapitalist]

Southern cotton exports enjoyed an almost unbroken stream of annual increases in the three decades prior to the rebellion. How was southern trade stifled?

From 1846 to 1860 the average US tariff rate either remained the same or decreased from one year to the next. There was not a single tariff hike in this period, thus trade was not stifled. Before 1846 tariffs were significantly higher and still protectionist, but even they showed a downward trend from the peak rates in 1828 save a few intermittent hikes. When taxes on trade go down at a near-continuous rate it is not at all surprising that trade will also grow at a near continuous rate. All that changes though when you take a low tax rate and triple it overnight, which is exactly what the Morrill Act did in 1861.

[Non-Sequitur]

So...tariffs go up and cotton exports go up. Tariffs go down and cotton exports go up. Tariffs remain the same and cotton exports go up. Damn those tariffs anyway!