Do attack ads crush the opposition?

A string of headlines about Mr Webster’s stance on women, and audio clips of him talking, culminates in the legend “Taliban Dan Webster” written in vaguely Arabic looking script.

It drew fire with critics saying it had taken Mr Webster’s comments out of context and edited them misleadingly.

A poll highlighted in the New York Times, external suggests Mr Grayson lost much support in just one week after the release of the ad.

This year’s US primaries saw some fruity adverts, with the Demon Sheep ad, external already notorious in the field of attack ads. Carly Fiorina attacked her Republican rival’s fiscal credentials.

But who would have thought that such mainstream subject matter could result in an internet video featuring a man dressed as a sheep sporting demon eyes? It generated criticism but also much buzz.

Having dealt with her Republican rival, Ms Fiorina must now deal with incumbent Democrat Senator Barbara Boxer.

Her strategy involves both short ads like her criticism of Ms Boxer, external for insisting on being addressed as “senator” and longer internet ads like the extraordinary Hot Air: The Movie, which depicts Ms Boxer as a giant hot air balloon of egotism.

Ms Boxer’s own most recent attack ad, external focuses on Ms Fiorina’s record as an executive with Hewlett-Packard, outsourcing jobs to China.

It’s a battle royale in much the same way as the fight between billionaire Meg Whitman and veteran Jerry Brown for the office of governor. Ms Whitman has used the words of Democrat President Bill Clinton, external to damn Mr Brown.

And Mr Brown has been able to respond with an attack on Ms Whitman’s record as an Ebay executive, external.

Third party adverts can be even more vicious.

“In this election, there will be more third party advertising. Third party adverts tend to be more negative,” says Prof Ansolabehere.

This advert from the National Republican Senate Committee, external is an example, attacking Illinois Democrat Senate candidate Alexi Giannoulias for having links to organised crime through his brother.

The best are short and pithy, says Prof Ansolabehere, with Connecticut Republican Senate candidate Linda McMahon’s attack on her Democrat opponent, external being a good example.

“That is a pretty good character attack, straightforward, grainy black and white images.

“A 30 second advert is four or five sentences. It is a little tiny narrative about the candidate.”

Democrat rival Richard Blumenthal’s own ads again take advantage of his opponent’s business background, external.