Close elections: They seem to be popping up all over. Earlier this month, in Mexico, Felipe Calderon, candidate of President Vicente Fox's PAN party, was declared the winner over left-winger Andres Manuel Lopez Obrador, winning 36 percent of the vote to Obrador's 35 percent. Earlier this year, in Italy, incumbent Prime Minister Silvio Berlusconi's center-right coalition lost to former Prime Minister Romano Prodi's center-left coalition by a popular vote margin of about 22,000 votes. Canada and Germany have governments headed by leaders of center-right parties that have only a plurality of parliamentary seats and came in ahead of their center-left predecessors by small margins. And, of course, in the United States, we have President George W. Bush, who was first elected in 2000 after a 36-day controversy over the results in Florida where he won by less than 1,000 votes of nearly 6 million cast.

Is this a trend? One thoughtful observer, blogger Lexington Green of chicagoboyz.net, notes that "The current technology provides the managers of campaigns [with the means] to do focus-grouping and constant polling and ads made to respond to minute changes in the opinion of the electorate, and to use computers to identify areas where the vote needs to be gotten out, and all kinds of things I don't know about." He goes on to ask, "Can it be that the tools are so refined that they are getting better and better at finding the marginal voter in the center, and that we are likely to have an increasing number of very, very close elections?"

Possibly. But close party divisions are nothing new. In the United States, from the end of the Civil War until the big Republican sweep in the congressional elections of 1894, the margins between the parties were very close indeed. In that age, long before computers, Republicans held the presidency most of the time (twice while losing the popular vote), while Democrats held a majority of seats in the House most of the time. With few exceptions, neither party got much more than 50 percent of the popular vote in presidential or House elections. This deadlock persisted for almost 30 years.

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.