The Columbia Accident Investigation Board killed the Space Shuttle, Not Obama. The shuttle was allowed to finish ISS, and actually flew a bit longer than CAIB envisioned. Obama did kill the Constellation replacement program.
Any chance he just wanted us out of the space business, to turn space into a Russo-Chinese playground and weapons platform?
Oh, and I thought I heard (correct me if I'm wrong) that Obama did nix some plans to extend the shuttle for a couple of years, even as an unmanned cargo truck for ISS deliveries.