Obama nominates Sebelius successor

(CNN) – President Obama will nominate Sylvia Mathews Burwell as the next Health and Human Services Secretary.

"I hope the Senate confirms Sylvia without delay," Obama said. "She's gonna do great."

Burwell is the current head of the administration's Office of Management and Budget. She would replace Kathleen Sebelius, who was the agency's chief during last fall's firestorm over the rollout of the Affordable Care Act and its problem-plagued website, which led to republican calls for her resignation.

Last month, Sebelius told the president she'd stay with the administration until the March 31 enrollment deadline.

Kathleen Sebelius, my Secretary of Health and Human Services, told me she'd be moving on once the first open enrollment period under the Affordable Care Act came to an end," Obama said. "And 7.5 million Americans have signed up for health coverage through the exchanges. She's earned that right."

Despite the controversy, the former Kansas governor said she is proud of what the administration has accomplished.

"This is the most meaningful work I've ever been a part of," Sebelius said. "In fact, it's been the cause of my life.

Obamacare remains a target of republicans this midterm election year.

"Republicans are going to use this confirmation hearing to drag out every problem that they see with Obamacare, that people lost their insurance plans, they think the law -- it costs too much money, they think the Secretary has too much control over the decisions in the law," Politico Health Care reporter Jennifer Haberkorn said. "That's going to be a huge point of contention."

A veteran of the Clinton Administration, Burwell joined the Obama Administration in April 2013.

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