Kathleen Sebelius' departure as President Barack Obama's health secretary signals a new chapter in the White House's efforts to defend Obama's signature healthcare law and help Senate Democrats who face tough battles for re-election in conservative states this fall.
In the tightly orchestrated transition that included Sebelius' resignation late Thursday and Obama's quick appointment of well-regarded budget director Sylvia Mathews Burwell as Sebelius' replacement, the political calculus was clear:
Having stood by Sebelius during a painful few months when Obamacare's rollout was marred by a balky enrollment web site, stinging criticism from Republicans and falling popularity ratings for Obama, the White House saw a chance to reset the national conversation over Obamacare amid good news, and with a new face in charge of the program.
Sebelius leaves at a time when most of the web site's problems have been fixed and enrollment in private health insurance programs through the Affordable Care Act has soared past the first-year goal of 7 million - a result that seemed unimaginable during the program's darkest days last fall.
For Obama and his fellow Democrats, one of the political risks of Sebelius leaving office during Obamacare's launch was that the Senate confirmation hearings that would follow for her replacement would amount to an embarrassing review of Obamacare's shortcomings.
Sebelius' departure is an indication that the White House, with Obamacare showing signs of success, is now ready have such a public, national debate over the program during Burwell's confirmation hearings.
As a fresh face steering the healthcare initiative, Burwell will have the advantage of not being "saddled with all the baggage of the political fights that came before," said one senior U.S. official who was not authorized to speak publicly.
White House officials said on Friday that Sebelius, a former Kansas governor, was not pushed out as secretary of Health and Human Services. They said she approached Obama last month about leaving.
However, Sebelius had given people close to the administration the impression that she had planned to stay in her job at least through the Nov. 4 elections, when control of Congress will be at stake.
In announcing Sebelius' departure and Burwell's appointment in the White House's Rose Garden on Friday, Obama seemed to emphasize Burwell's competence.
He described Burwell as a "proven manager" who "knows how to deliver results," a quality needed because of the "big challenges" that lie ahead for Obamacare, which is designed to help millions of uninsured and under-insured Americans.