What happens if James Buchanan of Pennsylvania was chosen as the Democratic nominee in 1852 instead of Franklin Pierce?
He will almost certainly beat Scott--the Whigs are just too divided on the Compromise of 1850 (whereas the Democrats by now are pretty united behind it--even the southern fire-eaters who originally opposed it). Like any conceivable 1852 Democratic candidate except Sam Houston (and just possibly William Marcy) he will support the Kansas-Nebraska bill in 1854. If it goes through, Kansas will be in just as great a mess as in OTL. Moreover, if one can judge from 1857-61 Buchanan's administration is likely to be more corrupt than Pierce's. For all these reasons, I doubt that he will be renominated in 1856. Just who the Democrats will turn to, though, I'm not sure. Douglas is the obvious alternative but is controversial--maybe former Governor Horatio Seymour of New York will emerge as a compromise candidate? In any event, I think 1856 is probably a bit too early for the Republicans to win the presidency.