Mindful that the new health care law’s ability to slow rising medical costs will depend to a great extent on how it is put in effect, President Obama is assembling a high-level team to carry out key elements of the overhaul and is considering moving faster than the law requires to put them into action. Sebelius has begun work on the first of what will be numerous regulations for Medicare, Medicaid and private health care providers. The secretary can expand successful ideas nationwide without Congress's permission. Mr. Obama, whose legacy will be shaped less by the law's passage than by...