Sebelius resigned yesterday ending her five-year tenure marred by troubled roll-out of Obamacare.
Obama has accepted her resignation and is expected to announce to nominate Office of Management and Budget Director Sylvia Mathews Burwell as her replacement.
In past few months, Sebelius faced criticism from various quarters in view of the troubled launch of the federal online insurance marketplace and the costs of the Affordable Care Act.
Earlier in the day, Sebelius testified before a Congressional committee where she announced that the enrollment for Obamacare has surpassed 7.5 million.
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Senator Chuck Grassley, in a statement, said anybody put in charge of Obamacare would be set up to fail.
"Sebelius was asked to promote something unready, poorly structured, and unpopular. She was given a law that was just about written in pencil the way the deadlines changed all the time. That put her in a position of having a strained relationship with Congress," Grassley said.
"It's disingenuous for the White House to distance itself from the problems and attribute them to partisan sniping at one member of the Administration. The next secretary might have a fresh start with the public and Congress but the flawed law is still the law," he said.
"She has been the key figure in the day-to-day work of implementing the law and securing new protections for patients. Her legacy will be found in the 7.5 million Americans signed up on the marketplaces so far, the 3.1 million people covered on their parents' plans, and the millions more gaining coverage through the expansion of Medicaid," Pelosi said.