Lesser evilists like to argue that Obama is .1%, or whatever, less harmful, than a hypothetical Republican. As in criminal law, one can speak of both the act and the intent regarding the exercize of power. (I use this distinction for argument's sake only, for reasons I hope will become clear later.) The .1% claim deals, in theory, with the largely quantifiable results of actual policies. In other words, the acts and their effects. I'd be the first to accept that, given the non-uniformity of history slices, effects vary from one administration to the next. Maybe Reagan was worse than Clinton. Maybe Bush was worse than Obama. In a set where nothing is of equal value to anything else, some are less bad than others.
I'm fine having the (f)act debate with lesser evilists on the conditions that, if I show that Obama has been worse, they'll stop supporting him as a matter of political strategy whereas if they show Obama has had less bad effects than a hypothetical alternative and that supporting people like him is the best strategy for non-oppression in the short- and/or long-term, I'll change my tune. We can talk about incarceration statistics, deportation statistics, war budget, etc. We can ignore what these actors intended, as it has no bearing on strategy. This is a conversation to be had with Chomsky, for example, who thinks voting Democrat is a good idea in spite of his recognition that Democrats want the same thing as Republicans -- to stay in power by serving power.
On the other hand, there's the question of intent. Whereas Chomsky understands that politicians act on political, not ethical motivations, there is a far more common kind of lesser evilist -- the one who argues that the .1% less evil gap results directly from Obama being a decent guy. The argument, depending on the apologetic context, ranges from "decent guy in comparison to those evil Republicans" to "decent, even heroic, guy, period," though it's essentially the latter. All of this is unconscious and unanalyzed. Upon criticism, the committed apologist uses that post hoc rationalization machine we call consciousness to clean everything up, reinventing his own arguments as coherent, using blurry-eyed vision to plug a dam that's cracked through and through.
"Obama as not just less evil but actually a decent guy" rests on splitting Obama into politician Obama -- the one who does what he has to and yes, makes mistakes (he isn't perfect!) -- and ethical, well-intentioned Obama. Outcomes the Obamapologist likes are attributed to Obama's good intentions, that is, to ethical Obama. Outcomes he doesn't like are pinned on political Obama. (This is also, not at all coincidentally, the way small children cope with tyrannical parental behavior.)
Let me propose as a way to distinguish whether or not your favorite politician is acting on political calculation or on humanitarian intentions. It's a simple test: Did the politician act, non-accidentally, in a way that hurt his political career? This is only the first condition for the possibility of a politician acting as a not-politician. It is a condition I'm unaware of Obama having met. And given what is known about the American political system as currently constituted -- that non-power-accruing "intentions" are punished so consistently and devastatingly at so many junctures in the politicians' rise to a position of federal power that it's impossible for anyone to get away with them at that level -- the default best explanation is always political calculation at the exclusion of any other calculation. If Obama's time in office ends up leading to the end of the drug war or the military industrial complex, that will almost certainly have been a product of Obama the shrewd political actor, and not Obama the guy who actually gives a shit about things like not destroying countless lives (considering that he has established, time and again, with his actions, that he does not give such a shit). This is also why you shouldn't "give credit" to political actors (where of course ethics/good intentions are implied), as some like to do.
It's possible, one might argue, for an act to be both political and ethical. A politician might, for example, use diplomatic means to secure the release of hostages. He might go along with a popular push against legislating sexuality. The politically savvy move can be the ethically decent move. But it's not ethical, intentionally, if it's first political, which, given the context, it always is.
Finally, given that no one knows what their intentions are outside simplistic, distorted representations in consciousness coming from godknowswhere and given that all intentions self-present, finally, as good, the most reliable way to talk about intentions where actions repeat (i.e. non-accidentally) is to assume that the action is the intention or that the actor is insane, or both.