Whoa, that was a DAMN close call with the canister at that mall. I thought for a while that maybe Kim would be in the mall, and that she and Jack would have a really interesting/awkward/typical 24-style reunion.
And I'm also glad to see that the First Lady is finally starting to learn about the subtleties of the game that is politics. Had Cummings not offed himself, it TOTALLY would have been alright to brand him a traitor. However, since he DID die, would it REALLY have done any good to drag his name through the muck? And like Mike Novic said, you've gotta think about the wife (and kids, if any). Husband/daddy's dead. Gone. Never coming back. Imagine the trauma and emotions that they're no doubt going through. Telling the family that Cummings was a traitor (at this point) would serve no useful purpose. Only thing it would do would be to piss off Cummings' family, who (theoretically) could have then gone with to the press and accused the President/First Lady of slander, thus hurting the administration, and everyone in general.
Usually, telling the truth is the best way to go. However, there are also times when, to protect the emotional well-being of people, it's better to not reveal the WHOLE truth.