That is exactly the point. Lincoln had no intentions of leaving those 7 states alone.
He did not think that they had the right to seceed, as has been discussed here before. His ego would not allow the southern states to defy his authority. The States under the Declaration of Independence, and the 9th and 10th Amendments, thought that they indeed had this right. And it was a common belief even from the Hartford Convention and William Rawle's writtings. Which is one of the points of Constitutional Law interpretation, which I was talking about. And one of the divisions of powers delegated to the President, to the Federal Government, and the individual states.
Those debates started in 1776 and came to a head on December 20th, 1860. After all the threatened secession of all the other states in the history of the United States prior to 1860, It was South Carolina who finally put that political theory to the test. That almost happen in 1832 Nullification Crisis and had nothing to do with anything that was going on in 1860 except that in both cases it challenged the authority of a federal government, and the make up of the country, should secession should be allowed.
Of course mistrust of the federal Government, the failure to control radicals elements in the north who violated the laws, southern hotheads, Taxes, export and imports, slavery and all the other elements played their parts. But, would any of those elements, or combinations of elements, have pushed us to war had South Carolina, followed by 6 other states, NOT seceeded?
I will point out this same political theory of secession has still not been answered under the Constitution in a Court of Law and is still being talked about even today. Yes, the US Supreme Court made a ruling. But, was it an honest decision without political influence? The Question of the legality of secession was not answered by the War for Southern Independence. It was mearly set aside by the strenght of a force of arms.