This is not to dispute anybody but I believe it is information like these(below) that causes confusion or maybe creates an urban legend.
Yes, I would say some information can cause a bit of confusion.
While the full articles on CafePress and Threadless do give some good insight into IP laws, some of it can be misleading and does not tell the whole story. But I would say it's not meant to be legal advice, just an effort to define what is eligible to be submitted on their sites.
The excerpts you posted from CafePress and Threadless are simply claiming that usage of political figures is allowed. But what about the copyright of the photo?
The Wiki answer focuses on whether the image is copyrighted or in the public domain. But what about Right of Publicity?
My point is, while these bits of information may be correct, none of it tells the whole legal story.
And as far as political figures being an "exception" or "fair game," there is no law that prohibits elected officials from bring action against infringement. While they may give up certain rights when taking office, their right of publicity is not one of them:
"C. Politicians and the Right of Publicity Although politicians rarely bring right of publicity actions, that does not mean they are actually barred from bringing them." Source:
BC Law Intellectual Property & Technology Forum & Journal - The Presidential Right of Publicity