[DiogenesLamp]

Except that nobody was telling the South it had to do anything in November 1860 when Fire Eaters began organizing to declare secession and then (May 6, 1861) war against the United States.

Well yes they were. They were telling them that they had to funnel all their trade through New York. To do otherwise would have cost them enormous fines and penalties, up to and including the loss of the entire cargo and any ship carrying it.

[BroJoeK]

"They were telling them that they had to funnel all their trade through New York."

And yet... and yet, that condition existed for several DECADES before 1860 without ever being considered a valid reason for secession.
Nor did ANY "Reason for Secession" document mention it.

What they did mention, nearly all of them, and most at great length, was, yes, slavery.

[Bull Snipe]

They were telling them that they had to funnel all their trade through New York. To do otherwise would have cost them enormous fines and penalties, up to and including the loss of the entire cargo and any ship carrying it.

Which law passed by Congress and signed by the President authorized those actions?