Ta-Nehisi says it well:
I believe that while a good politician accomplishes what is possible, a great one expands the realm of possibility. He doesn't simply accept the lines of argument as their drawn and hew to the side with the most soldiers, he tries to redraw those lines to benefit his ideals. Obama's jobs isn't simply to spend his own political capital, it's to grow his capital, and by extension, the moral weight of his ideals. Perhaps pushing torture investigations would make passing health care harder. But this is the business he chose. This is the business of becoming great. And after what happened last year, we have the right to expect more of him. We have the right to demand more.
This is one core reason I supported him. My endorsement, which focused almost exclusively on undoing the Cheney regime of total executive power and torture to buttress it, is here. Money quote:
If I were to give one reason why I believe electing Barack Obama is essential tomorrow, it would be an end to this dark, lawless period in American constitutional government...
We cannot be a beacon to the world until we have reformed ourselves. In this war, we are also fighting for an America that does not lose its soul in fighting our enemy. Just because we are fighting evil does not mean we cannot ourselves succumb to it. That is what my Christian faith teaches me - that no nation has a monopoly on virtue, and that every generation has to earn its own integrity. I fear and believe we have given away far too much - and that, while this loss is permanent, it can nonetheless be mitigated by a new start, a new direction, a new statement that the America the world once knew and loved is back.