You are overlooking a third source, payments from domestic sources who then sold that cotton abroad. Which would allow the southern planter to spend his money domestically. Assuming, as you seem to be doing, that the planter spent all his money on imports leaves nothing to sustain the domestic economy with or to buy more slaves with.
But he is saying that Lincoln will go to war over it.
Which is nonsense since, as Senator Simmons pointed out, we're only talking about $3 million in revenue. That's less than 3% of the total revenue estimated by Senator Simmons. Nobody would go to war over a minor issue like that. President Lincoln must have been motivated by something else, like preserving the Union.
Your economic ignorance is showing again. Such persons are intermediaries in the market. They act at levels in between a good's production and its reciept by the ultimate buyer. The tariff costs etc. are ultimately transfered through their presence though by way of price.
Assuming, as you seem to be doing, that the planter spent all his money on imports
Not at all. You are again missing a key economic concept of trade. Trade does not occur out of the goodness of a seller's heart, non-seq. If I give my cotton to a buyer in Britain, I do so only because he is giving me something in return for that cotton. It may be a payment in money that he gives me. It may be manufactured goods of his own. It may be another foreign product sent to America by a roundabout way through what I use that cash on. But in the end, the only reason I will give him my cotton is because I get something in return for it. When the south as a whole trades out $220 million worth of products, they expect to get payment in return - either return products or money. And if the government puts a tariff in the way that blocks those return products from getting here, the whole circle of trade halts because the south isn't going to simply give away its cotton without something in return.
Which is nonsense since, as Senator Simmons pointed out, we're only talking about $3 million in revenue.
Not at all. As Clingman pointed out, goods can come in anywhere by sea on the North American continent. If New York has a tariff blocking goods from entering and Charleston does not have such a tariff, the foreign shippers will go to Charleston to avoid paying that tariff and the good is delivered. As a result, nothing will come in through New York and if nothing comes in through New York, no taxes are paid. The confederacy created exactly that kind of a situation for New York, and in doing so threatened to undermine the entire northern government's redistributionary government intervention-based economy. And if you still doubt Senator Clingman's arguments, answer me this - why were these exact same arguments used by the New York Times, an indisputably pro-north newspaper, only two weeks later in an effort to pursuade Lincoln to go to war?