The Bush administration might have not supported calls for a new draft, because they feel that they are not yet ready for it at the moment. A new draft comes with new things that they may not yet agree with for now.
The US has a great volunteer army so there is no need for a draft. As long as there are enough volunteers we dont need a draft and instituting a draft would be a VERY unpopular and VERY politically destructive move for any politician. No one wants the draft.