Kathleen Sebelius, who helped guide the rocky and controversial rollout of US President Barack Obama's landmark health care law, is stepping down as Health and Human Services secretary after about five years, according to a senior administration official.
In her place, the president plans to nominate Sylvia Mathews Burwell, director of the White House Office of Management and Budget.
Sebelius was not pressured to resign, according to the administration official. But she leaves after presiding over the disastrous launch of the health law's new online insurance marketplaces last fall. The failure threatened to unravel what was supposed to be Obama's signature domestic policy achievement and has endangered Democrats who face re-election in November.
The federal website, HealthCare.gov, was riddled with glitches that made it almost impossible for people to sign up for health insurance for weeks. Although the website has been repaired and enrolment has recovered strongly, the debacle continues to baffle many outside experts who have blamed weak leadership at the White House and the health agency Sebelius heads.
Sebelius, a two-term Democratic governor of Kansas, was once seen as a rising star in the Democratic Party, but her department's troubles with Obamacare led to calls for her resignation.
In testimony before Congress after the website's flaws had drawn headlines, she said: "I am as frustrated and angry as anyone with the flawed launch of HealthCare.gov. So let me say directly to these Americans, you deserve better. I apologise. I'm accountable to you for fixing these problems. And I'm committed to earning your confidence back by fixing the site."
Obama remained publicly supportive of Sebelius throughout the rough rollout, deflecting Republican calls for her resignation. But she was conspicuously not standing by his side last week when he heralded the sign-up surge during an event in the White House Rose Garden.
An administration official said the 65-year-old Sebelius approached Obama last month about stepping down, telling him that the sign-up deadline was a good opportunity for a transition and suggesting he would be better served by someone who was less of a political target.
Burwell is an alumna of the Clinton administration, where she worked as deputy director of the budget office from 1998 to 2001. She then worked for a decade at the Bill & Melinda Gates Foundation, including as chief operating officer. She most recently headed the Wal-Mart Foundation, the philanthropic arm of the retail giant Wal-Mart Stores Inc.
Credited for her experience in and out of Washington, she was unanimously confirmed last year for the budget post, long considered one of the most important White House jobs.
She is almost certain to face opposition from congressional Republicans when she is nominated for health secretary, as GOP lawmakers remain focused on doing everything possible to derail the 2010 Affordable Care Act. But a change in the filibuster rules in the Senate will allow Democrats there to confirm her with a simple majority, obviating the need for any Republican votes.
-MCT with AP