One problem, you cannot.
You can't just try and remove one of the MAJOR facets behind the Civil War's beginning and expect people to go along with it. Much of the motivations and reasons behind the war then lose their meaning, and then where are you?
All wars have unintended consequences. The Treaty of Versailles financially slaughtered a Germany that - due to propaganda - was utterly shocked at the military's acquiescence to the terms. That shock would give way to indignant anger at the ludicrously large reparations, which would give rise to the frustration that birthed Hitler. So despite the victory of the Allies, an even bigger war had its foundations formed.
Victory in World War II enabled Soviet Russia to try and maintain a 'land barrier' between itself and Germany, fearful of future invasion. This necessitated Communist maintenance of the nations in-between. America and Britain were utterly opposed to this. Combine this America's attempts at rebuilding and refurbishing both Germany and Japan, and you have nationalistic distrust of America by both Russians and Chinese. This mistrust would become a foundation of the Cold War, and the American connection with the Guomindang would part of the reason for the eventual Communist victory in China, circa 1949.
ALL WARS HAVE UNINTENDED CONSEQUENCES.
We have to deal with them as they happen. During the midst of something like a Civil War, where it was American against American, I highly doubt that the increase of federal power wouldn't have occurred.
You'd have better luck trying an argument about the negatives of an increase in federal power during the Wilson Administration during World War I, during FDR's New Deal, during LBJ's Great Society, and during Nixon's Administration than you would have arguing the negatives of increased federal power during the Civil War.
Do you think burning half of Georgia to the ground might be an example of "an increase in federal power"?
Why not? You hero - Lincoln went on record saying if he could stop the war by not freeing any slaves he would. You drank the liberal historical kool aid. Try to expand your mind. We are in a political fight with brain dead monitizing Fedzilla right now, it might help if you revisited history from a different perspective to try and figure out a peacefull way to stop the beast this time. You are not helping.