Misstatement on my part due to my not reading your statement carefully enough. For the record I do not believe that Lincoln and the Union pursued the war that was forced upon them for the purpose of ending slavery. Nor does anyone who has studied the rebellion in any depth. Except, perhaps, you but then I have no idea how much time you have spent looking into the history of the rebellion. Since you insist on referring to it as Lincoln's war then I'm thinking not much.
That is the only answer a knowledgeable northerner can give when there is an interest in claiming Lincoln loved the union and the constitution he twice swore to uphold.
If Lincoln was found to be fighting and killing to “free the slaves” he would have been guilty of the violent overthrow of the U.S. constitution - which enshrined slavery. And I don't think you want to go there. The supporters of John Brown gladly go there, but I don't think you want to go there.
That said, there is actually evidence that Lincoln did intend to violently overthrow the constitution. Reminds me of Barack Obama who famously ran for president as a “strong advocate that marriage is between one man and one woman” and later “evolved” into the opposite. Who can really say for sure what the intent of Lincoln was other than to get power and keep power for the purpose of advancing the economic and political best interests of the North.