Bottom lines have stayed parked at these stratospheric levels despite a steady loss of viewers, first to cable and more recently to the Internet. In a world where audiences keep getting sliced thinner, the medium that attracts the most viewers keeps getting more valuable, even as it loses eyeballs. That's still broadcast television. Eye-popping as this growth has been, it still doesn't measure the full economic impact of political ads. But the rule works better in theory than in practice.
Candidates are an unusual breed of advertiser.
In order to ensure that their ads reach the right audience at the right time, they need to buy what's known as non-preemptable time. It's the most expensive time on every station's rate card. There are more. Product advertisers have responded by adopting an edgy tone that tries to engender good feelings about a brand by poking fun at the very act of advertising it. When it works, it's among the best stuff on television.