Barack Obama has done more to expand government than any president since Lyndon B. Johnson, but the Gulf oil crisis is testing his ability to master the federal bureaucracy in a way no other crisis has — with decidedly mixed results. The first president since John F. Kennedy to take office without executive branch experience, Obama has struggled for the past month to find the right balance between micro- and macro-management as the Deepwater Horizon spill has grown into an environmental cataclysm and political disaster. People who have worked closely with Obama say he doesn’t think like a bureaucrat, is...