Sebelius hands in resignation

After months of defending Obamacare and its rocky online rollout, Kathleen Sebelius is stepping down as secretary of the Department of Health and Human Services.

Her resignation comes just one week after the end of the initial enrollment period for President Barack Obama’s signature healthcare law. But when Obama made his announcement last week that enrollments had exceeded 7 million at a press conference in the White House Rose Garden, Sebelius was not present.

Despite her low profile in recent months, the president often defended Sebelius, even after her rattled appearances testifying before Congress and a disastrous interview on The Daily Show with Jon Stewart last fall.

Obama will nominate Sylvia Mathews Burwell, the director of the Office of Management and Budget, to replace Sebelius. “The president wants to make sure we have a proven manager and relentless implementer in the job over there, which is why he is going to nominate Sylvia,” White House chief of staff Denis R. McDonough told The New York Times.

Burwell, a West Virginia native, graduated from Harvard and Oxford and has a background in economic policy. Previously, she was president of the Walmart Foundation and president of the Global Development Program of the Bill and Melinda Gates Foundation.

Sebelius’ resignation could set the stage for a contentious election-year confirmation hearing to replace her, as Republicans plan to make Obamacare the centerpiece of their efforts to retake the Senate majority in November.

The Associated Press contributed to this report.