We don't have a canonical expression for "propaganda" (that I know of), but you might consider something like:
vuD SIghwI' - "opinion influencer"
vuD SIghmeH jInmol - "a project for influencing opinions"
...or perhaps even:
roghvaH vuDmey SeHchu'meH jInmol'a' - "a grand scheme for completely controlling the opinions of the population"
You could simplify this to phrases with SIghmeH, like SIghmeH SoQ propaganda speech, SIghmeH De' chu' propaganda news, SIghmeH jIH much propaganda television/movie. It doesn't carry the connotation of government-run-amok that the modern English propaganda tends to have in the United States. It could be used for an anti-drug campaign as well, which is technically propaganda, but we don't usually use that word for it.