The Collaborative International Dictionary of English v.0.48:

Manifesto \Man`i*fes"to\, n.; pl. Manifestoes. [It. manifesto.
   See Manifest, n. & a.]
   A public declaration, usually of a prince, sovereign, or
   other person claiming large powers, showing his intentions,
   or proclaiming his opinions and motives in reference to some
   act done or contemplated by him; as, a manifesto declaring
   the purpose of a prince to begin war, and explaining his
   motives. --Bouvier.
   [1913 Webster]

         it was proposed to draw up a manifesto, setting forth
         the grounds and motives of our taking arms. --Addison.
   [1913 Webster]

         Frederick, in a public manifesto, appealed to the
         Empire against the insolent pretensions of the pope.
                                                  --Milman.
   [1913 Webster]

WordNet (r) 3.0 (2006):

manifesto
    n 1: a public declaration of intentions (as issued by a
         political party or government) [syn: manifesto,
         pronunciamento]