James Button, one-time speech-writer to former Australian Prime Minister Kevin Rudd, wrote this in his recent book:

When Rudd spoke at the Department’s Christmas party, he had sketched a triangle in the air that distilled the work of producing a policy or speech into a three-point plan:  where are we now; where do we want to go and why; how are we going to get there?  The second point – where do we want to go and why – expressed our values, Rudd said. It was a simple way to structure a speech and I often used it when writing speeches in the year to come.” (Button 2012, page 55, large print edition).

Reading this I was reminded how inadequate I had found the analysis of political speech propounded by anthropologist Michael Silverstein in his short book on political talk (Silverstein 2003).   He seems to view political speech as mere information transfer, and the utterances made therefore as essentially being propositions – statements about the world that are either true or false.   Perhaps these propositions may be covered in rhetorical glitter, or presented incrementally, or subtly, or cleverly, but propositions they remain.   I know of no politician, and I can think of none, who speaks that way.   All political speeches (at least in the languages known to me) are calls to action of one form or another.   These actions may be undertaken by the speaker or their political party – “If elected, I will do XYZ” – or they may be actions which the current elected officials should be doing  – “Our Government should be doing XYZ.”     Implicit in such calls is always another call, to an action by the listener:  “Vote for me”.    Even lists of past achievements, which Button mentions Rudd was fond of giving, are implicit or explicit entreaties for votes.
Of course, such calls to action may, of necessity, be supported by elaborate propositional statements about the world as it is, or as it could be or should be, as Rudd’s structure shows.   And such propositions may be believed or not, by listeners.  But people called to action do not evaluate the calls they hear the way they would propositions.  It makes no sense, for instance, to talk about the “truth” or “falsity” of an action, or even of a call to action.   Instead, we assess such calls on the basis of the sincerity or commitment of the speaker, on the appropriateness or feasibility or ease or legality of the action, on the consequences of the proposed action, on its costs and benefits, its likelihood of success, its potential side effects, on how it compares to any alternative actions, on the extent to which others will support it also, etc.
What has always struck me about Barack Obama’s speeches, particularly those during his first run for President in 2007-2008,  is how often he makes calls-to-action for actions to be undertaken by his listeners:  He would say “We should do X”, but actually mean, “You-all should do X”, since the action is often not something he can do alone, or even at all.  “Yes we can!” was of this form, since he is saying, “Yes, we can take back the government from the Republicans, by us all voting.”    From past political speeches I have read or seen, it seems to me that only JFK, MLK and RFK regularly spoke in this way, although I am sure there must have been other politicians who did.  This approach and the associated language comes directly from Obama’s work as a community organizer: success in that role consists in persuading people to work together on their own joint behalf.  Having spent lots of time in the company of foreign aid workers in Africa, this voice and these idioms were very familiar to me when I first heard Obama speak.
Rudd’s three-part structure matches closely to the formalism proposed by Atkinson et al. [2005] for making proposals for action in multi-party dialogs over action, a structure that supports rational critique and assessment of the proposed action, along the dimensions mentioned above.
References:
K. Atkinson, T. Bench-Capon and P. McBurney [2005]: A dialogue-game protocol for multi-agent argument over proposals for action.   Autonomous Agents and Multi-Agent Systems, 11 (2): 153-171.
James Button [2012]: Speechless:  A Year in my Father’s Business.  Melbourne, Australia:  Melbourne University Press.
Michael Silverstein [2003]:   Talking Politics:  The Substance of Style from Abe to “W”.  Chicago, IL, USA:  Prickly Paradigm Press.