The politicians got very skilled at using the high-tech methods of the day to maximize their vote, dispensing public jobs and organizing enormous torchlight parades to rally voters. But it's also true that voters believed great things were at stake. The Republican Party had prosecuted and won the Civil War and freed the slave; vast blood had been spilled in what Republicans believed was a righteous cause. Democrats were of another mind. Southern Democrats or their fathers had been secessionists, bleeding for the losing side, and Northern Democrats were lukewarm at best about the war effort and dubious about the results. Northern Democrats successfully got Union troops removed from the Reconstruction South, and Southern Democrats set about disenfranchising the freed blacks and, in the process, created the Democratic Solid South that persisted until the 1950s.
Today, politicians in closely divided countries have become extraordinarily skillful in maximizing their votes, using the latest high-tech tools. George W. Bush's Republicans in 2004 assembled 1.4 million volunteers and used computer data relating commercial preferences to political belief to turn out previously unregistered Republicans. But voters' strong convictions on issues that cleave the nation almost precisely in half are also responsible for the close margins. The United States seems divided in a kind of culture war, with religiously observant people voting heavily Republican and the secular heavily Democratic.
In Mexico, the split is economic, but not precisely along income lines; Calderon ran about even with Lopez Obrador among the lowest income voters. Instead, the split is between a northern Mexico, with 40 percent of the population pulsating with free market economic growth, and metro Mexico City and southern Mexico looking to government for sustenance.
In Italy, the split is between the south, which has been voting center-right since American GIs liberated it from Mussolini, and the "red belt" north of Rome, where Communist partisans still fought the Nazis until 1945. Canada is split between separatist Quebec, statist Toronto and the libertarian west. Germany is split between a once-Protestant, socialist-leaning north and a once-Catholic, more market-oriented Rhineland and south.
Today's politicians try to maximize the appeal of their platforms and the turnout on their side of these enduring divisions, with the result that elections tend to be close. But that may not always be so. As new issues arose, the post-Civil War division of the United States yielded to a generation of Republican majorities and then a generation of New Deal Democratic dominance. Something like that, here or abroad, could happen again.