Obama progressives have a lot riding (everything?) on one proposition:
"Obama is doing the best he can (or close to it) under the circumstances."
The scenario is something like this:
There's a prison that has one guy in charge. It's this person's job to kill at least one prisoner a day and torture five a day. If he doesn't, he'll lose his job and have to go back to being a lawyer. Now, he took this job, the progressive speculates, because he thinks he can do it with less brutality than the other candidates would have. He doesn't want to do the bad things, and by doing less of them than a hypothetical alternative (a Republican!), he's actually doing a good thing. He'll find ways to torture less, perhaps. He'll pretend he's executed someone but without anyone seeing, he'll sneak them out an escape tunnel while presenting a fake corpse to the bosses. He'll make the most of that space between the bad things he has to do and the good things he can do without getting caught.
You can never finally disprove this. The believer can always get around demonstrable evil, even things they agree are evil (though they'll try to talk down the level of evil to kinda bad or mistakes), because they've started with their conclusion that Obama is good and all examples to the contrary have a ready-made irrefutable but baseless explanation.
Most Obama progs I know personally are non-religionists (contradiction in terms? yes, I'm getting to that) so let me back up and use methodology they're familiar with. Here's a hypothesis:
"Obama is just like any other power-haver. Obama does not do anything that will hurt his chances to hold onto power, anything that will hurt his chances for reelection and if reelected, will not do anything to hurt his chances at a (Bill) Clintonian ride off into the bestseller, speechgiving ex-prez sunset. This means he will continue the drug war that incarcerates millions, expand Presidential power, expand the military-industrial complex, expand government control of the internet, etc."
He will do the bad things. He has done them. There is no reason whatsoever to suspect that he's doing them against his will. There is no evidence at all pointing in that direction. He has not done anything, even your favorite thing that you think he's done, that cannot be best explained as having been calculated to increase his own hold on power. In other words, he'd like to kill two prisoners a day and torture six. He does not have bosses per se. He has cohorts and he has rivals. Most people he works with fall into both categories.
Here's another hypothesis: "No matter what happens, I know God loves me. God tests me sometimes, is all. Wife has cancer? The Lord works in mysterious ways. Won the lottery? God loves me. Bitten by a rabid donkey while trying to save a small child? Oh, God, you silly guy. What is up with you, man? Ha, I'll understand when I get to heaven. God loves everyone, as proven by..." nothing, of course. When good things happen, God gets credit. When bad things happen, God gets excuses. Evidence is not a factor.
Finally: "Whenever Obama does the good things, it's because he's good. Whenever he does the bad things, he's acting against his own will."
God doesn't want to hurt anyone. Obama doesn't want to hurt anyone.