You can listen to every stump speech and read every position paper, but nothing compares to evaluating presidential candidates side-by-side during a debate. Their contrasting styles and views emerge in ways you hadn't noticed during the long primary season. The candidates practice their lines and prepare their strategies, but the format allows for precious moments of spontaneity and even humor. The best candidates deftly address issues in ways that lodge them in the public consciousness.

Perhaps the best example of this is President Reagan, who in 1984 famously said, "I will not make age an issue of this campaign. I am not going to exploit for political purposes my opponent's youth and inexperience." His 56-year-old opponent, Walter Mondale, could only look on in laughter.

The first debate between Senators John McCain and Barack Obama provided no such memorable moments. But it did highlight important distinctions between the Republican and Democratic candidates. Namely, McCain and Obama ...