This post by my friend, Aria, is very insightful. He neatly links between utility theory and the principles of ushul fiqh. Namely, 1) "... Select the higher of the two benefits, or incur the lesser of the two harms when faced with them both", 2) "... Repelling harm takes precedence over procuring benefits", and 3) "... Certainty is not invalidated by doubt".
Now, with the risk of misinterpreting Aria's insight, let me take it to the current Indonesian politics. Given that there are only Megawati and SBY, I will vote for SBY. Why? (I personally don't see that not voting in this election is wise. You can't give your support; nor you can scream at a game if you keep avoiding paying for admission ticket -- you are simply outside. Some say that letting the ballot uncast wil give room for manipulation: ballot committee can be bribed to put a check on the empty ballot. Right. But the solution is not to put check mark on both options so as to invalidate the ballot. It might reduce modes available for cheating, true. But there are ways -- many ways -- other than that for manipulation (remember Florida case?). Then, why would I bother to vote if it might as well be manipulated? Well it will give me my ticket -- at least emotionally -- to support or to scream or to curse the players. Secondly, I don't feel good being indifferent -- and not voting is not a strategy (in the Game Theory sense) here. I will choose and bear the consequence. I won't use the oxymoron "choose not to choose". It's a little irresponsible) .
OK, back to Aria's points. Mega and SBY are "the harms". I think SBY is less harmful, though (the "contract" with PKS, and not with Golkar is an indication. Some doubt it. I say, give it a chance, and smash it if it turns lie -- you've got a ticket!). Next, I tend to believe that those in PKS have better intention than those in the other big parties. History has examples. The fact that they choose SBY as their "ticket", in my opinion, is more of a way to put control over him (this is "repelling harm") rather than to secure positions in the cabinet (or, "procuring benefits"). It is obvious that PKS can't capitalize on SBY being president -- too many interests around him, but at least it can remind him of his promises. And the people saw the sworn. Why not Megawati then? Don't tell me you don't know the answer. "Certainty is not invalidated by doubt".