Just my not so humble opinion, but one possible theory Hillary didn't torpedo obama with this issue in the primary is political Mutual Assured Destruction.
Clearly, obama has his secrets. But, Bill and Hill have a long, wide trail leading to, through and away from the WH, with a lot of bodies buried by the side of that trail and a lot of grave diggers to help with the clean up.
Is anyone really surprised that when the Chicago Way met the Arkansas Crime Family they found a way to work things out? You know, for the good of the party and all of that.
It is rare to hear this... but about 3 days before Hillary announced she was out of the race, she and Obama attended a Bliderberg meeting in Washington DC, which is where it was held that year. She and Obama both disappeared for three days in the middle of a hotly contested Primary race. When they re-appeared, Hillary said she was out and immediately there were discussions of her taking the Secretary of State position.
I think the writing with the angry black mob was on the wall, and the Bilderberg group convinced Hill to drop out, and Obama to make her SOS when/if he won.
http://www.prisonplanet.com/articles/june2008/060608_hillary_obama.htm Not the most unbiased source, but finding articles on Bliderberg in the MSM isn’t so easy.