The South was not necessarily at the center of American commerce and diplomacy in the 1860s. In fact, during this time period, the North was becoming increasingly dominant in both areas.
However, the South was a major center of agricultural production, particularly for cotton. The southern states had a large number of plantations that produced cotton, which was in high demand in Europe and other parts of the world. As a result, the South played a significant role in the global economy, particularly in the textile industry.
Additionally, the South played a role in American diplomacy during the 1860s due to the issue of slavery. The southern states were in favor of allowing slavery to continue, while many northern states were opposed to it. This led to significant political tensions between the North and South, which ultimately led to the secession of several southern states and the outbreak of the Civil War.
Overall, while the South was not necessarily at the center of American commerce and diplomacy in the 1860s, it did play a significant role in the global economy and American politics due to its important agricultural production and the issue of slavery.