Well, at least since 2004. According to the Pew Research Center's Project for Excellence in Journalism, the coverage of the Barack Obama/Mitt Romney race is "as negative a campaign as PEJ has seen since it began monitoring ... in 2000."
The 2004 campaign was about as negative, due to the focus on Iraq, Abu Ghraib and the Swift Boat veterans.
And more of the bile now comes directly from campaigns rather than the press.
Reporters (and talk show personalities) account for about half as many of the assertions about the candidates' character and biography as they did 12 years ago-27% versus 50% in 2000. At the same time, campaigns, their surrogates and allies now account for nearly half of these themes, 48%, up from 37% in 2000.
Both Obama and Romney are get equally bad coverage. The main negative line against Obama is that he has failed to do enough about the economy, followed by doubt that he believes in capitalism and individualism. The major knock on Romney is that he was a "vulture" capitalist, followed by the charge that he's elitist and out-of-touch.
But while the vast majority of Obama coverage (positive and negative) focuses on the economy, the narrative threads on Romney are more diffuse. Included in the top six are that he is gaffe-prone, that his campaign is well-organized and that his policies are vague.