Why the Close Elections?

In the Washington Times, sometime Reason contributor Bruce Bartlett argues that access to alternative media is spurring the oh-so-close elections we seem to have been experiencing the past several years. Apres talk radio came the Internet et voila:

There was finally a full blown conservative alternative to the decades-long liberal media domination. This, I believe, is behind the tightening of political races. Now both sides can get their message out with equal effectiveness, returning politics to the 19th century norm, before liberals took de facto control of all major media, creating an era of liberal political domination that was a historical aberration.

More here. Bartlett is responding to a Michael Barone col in which Barone posited sharp divisions on basic issues as the cause.

Outside of presidential races, I'm not convinced we are in some grand age of razor-thin contests. Isn't the conventional wisdom that gerrymandering has made U.S. representatives and senators even more bullet-proof than ever? But to the extent that presidential races have been close–and to my mind the most striking thing about the past four elections is that only one has produced a majority vote-getter, Bush in 2004, and not by much–maybe it's consensus on most issues that's providing the dead heats. Dem and Rep presidential candidates have been offering up an echo of each other, not a distinct choice, which might explain the weak vote totals as much as anything else.