No, president Lincoln couldn't have really prevented the war. Reason being, it didn't really have that much to do with him in the long run; his election was the final straw for an already angry south. Maybe Buchanan could have, but he didn't really pay much attention to he issue. The issues causing the civil war had been happening for decades before 1860, which had already began to divide the nation. Things just began to build on each other leaving the south to feel left out and not important. They didn't want Lincoln elected because of his stance on slavery in the future states in the West. They had already been threatening secession since tariffs in the 1820's. Lincoln didn't really have much say, as South Carolina seceded just a few weeks after his election. There wasn't really anything he could do to stop this from happening, it was just a matter of time.