Calhoun has a point, but we can still strengthen this. WWII was seen as a turning point for the presidency, because afterwards the office did not decline in influence or power, as had been the case in serious term. There's no reason the Civil War can't be seen as a similar turning point if, say, Benjamin Butler was Vice President, instead of Andrew Johnson. I imagine Butler will very much keep the powers Lincoln accrued, and more successfully than Johnson.