Attorneys representing California artist Shepard Fairey in his legal dispute with the Associated Press (AP) over copyright ownership of a Barack Obama presidential campaign poster image are now citing a legal defense called, the doctrine of unclean hands‚ to help negate claims of copyright infringement.

The doctrine states that parties cannot seek damages for an activity in which they partake themselves. Referencing this doctrine, Fairey's team maintains that the AP regularly uses images in stories without permission from the artist. As an example, the Fairey team cited an AP story from January showing Fairey's poster in transit to the Smithsonian Institution.

In addition to this latest defense, Fairey's attorneys say that the artist's work does not violate copyright laws because he, dramatically changed the nature of the image" which is protected by fair-use laws.

The legal feud began in February when the AP sued Fairey for copyright infringement on an image taken by AP photographer Mannie Garcia in 2006. At press time, no ruling had been reached.