So, the thread has gone full circle back to “what was the cause of the war”. I do find it interesting that you start with Lincoln’s inaugural address on March 4, 1861. Interesting starting point. I wonder, did anything of note concerning the Civil War occur before this date? How about the attempted secession of South Carolina on December 20, 1860? Do you think that might have something to do with the start of the Civil War? How about the other six states that seceded before this pivotal speech?
I also find it interesting, if the primary reason for the Civil War was the collection of tariffs, the government of South Carolina never saw fit to mention tariffs in their Declaration of Causes of the Secession. Neither did any of the other states that saw fit to give their reasons for Secession. Kind of interesting that the people who actually seceded didn’t mention their primary reason for seceding, isn’t it (by the way - what reasons did they give?)?
As far as the question you stated “What was so important about the conditions in April of 1861 that induced Lincoln to be willing to risk war?”, I would say that this was the soonest he could do anything about it - remember, he didn’t become president until March 4.
So, I will turn back the question to you - What was so important about the condition in December of 1860 that induced South Carolina to be willing to risk war?
It is unfortunate that you are now asking numerous questions that are circular and meant to obfuscate.
Maybe we should communicate another time.