IMO, this relates to political action rather than to politically-motivated art... but I could be wrong. Barbara will be able to figure out which applies here.

In any case, the French Wiki for "propagande par le fait" toggles to the English Wiki for "propaganda of the deed." The latter begins:
"Propaganda of the deed (or propaganda by the deed, from the French propagande par le fait) is a concept that refers to specific political actions meant to be exemplary to others."
FR: http://fr.wikipedia.org/wiki/Propagande_par_le_fait
EN: http://en.wikipedia.org/wiki/Propaganda_of_the_deed

Also see:
"The Propaganda of the Deed" (American Journal of Political Science)
http://www.jstor.org/pss/4620071

"Propaganda of the Deed" (American Spectator)
http://spectator.org/archives/2011/02/04/propaganda-of-the-d...

"Afghanistan: Propaganda of the Deed" (International Relations and Security Network)
http://www.isn.ethz.ch/isn/Current-Affairs/Security-Watch-Ar...

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Note added at 15 hrs (2012-02-23 13:56:44 GMT)
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To elucidate slightly, here's an excerpt from the American Spectator article:
"The basic justification for homicide bombings is what the famed historian Walter Laqueur has referred to in his terrorism writing as the "propaganda of the deed." The idea behind this form of political action is that a terrorist act that has a major public impact establishes the importance of the intended message as well as the threat of implied power which reverberates beyond the immediate political target. This concept did not work very well in the Domodedovo incident."
http://spectator.org/archives/2011/02/04/propaganda-of-the-d...