WASHINGTON — Members of Congress, including Democrats, have urged the Obama administration to search for another Medicare chief after concluding that the Senate is unlikely to confirm President Obama’s temporary appointee, Dr. Donald M. Berwick.
Dr. Berwick’s principal deputy, Marilyn B. Tavenner, has emerged as a candidate to succeed him. Lawmakers of both parties said Monday that Ms. Tavenner, a former Virginia secretary of health and human resources with extensive management experience, could probably be confirmed.
In a letter to the White House last week, 42 Republican senators urged Mr. Obama to withdraw the nomination of Dr. Berwick to head the Centers for Medicare and Medicaid Services, which runs insurance programs for more than 100 million people. If those senators stick together, they could block confirmation.
Mr. Obama bypassed Congress and appointed Dr. Berwick while the Senate was in recess last July. The appointment allows him to serve to the end of this year.
The president has nominated Dr. Berwick three times, most recently in January. No confirmation hearings have been held, and none are scheduled.
Reid Cherlin, a White House spokesman, said the president would not withdraw the nomination. “The president nominated Don Berwick because he’s far and away the best person for the job, and he’s already doing stellar work at C.M.S.,” Mr. Cherlin said.
It is not clear whether the White House will fight for the nomination or press the Finance Committee to hold a confirmation hearing, which could provide Republicans another opportunity to criticize the new health law.
Dr. Berwick, a pediatrician and a health policy expert, was hired to run Medicare and Medicaid. In recent weeks, the White House has expanded his portfolio to include federal regulation of private insurance.
As a co-founder of the Institute for Healthcare Improvement, a nonprofit organization in Cambridge, Mass., Dr. Berwick advised hospitals on how to save lives by upgrading care and reducing medical errors.
He became caught up in the partisan battle over the new health law. Republicans challenged him to explain comments in which he had discussed the rationing of health care, praised the British health care system and urged health care providers to reduce the use of ineffective procedures near the end of life.
At a hearing of the House Ways and Means Committee last month, Dr. Berwick said, “I abhor rationing.” Representative John Lewis, Democrat of Georgia, told Dr. Berwick, “I love your testimony, not just like it but I loved it.”
Republicans were hostile.
“In your testimony, I see nothing but platitudes,” Representative Charles Boustany Jr., Republican of Louisiana, told Dr. Berwick.
Representative Geoff Davis, Republican of Kentucky, said Dr. Berwick’s answers bordered on equivocation. And Representative Tom Price, Republican of Georgia, told him: “You missed your calling. I think you would make a great lawyer.”
Several people who work with Dr. Berwick at the Medicare agency said they were disappointed that the White House had not done more to promote him. “Everybody here admires Don and the work he’s done, but he is not going to be confirmed,” a supporter said. “That’s inevitable. The Republicans will block him. There’s not a lot of optimism that the White House can do anything about it.”
Ms. Tavenner, a nurse, worked for more than two decades at the Hospital Corporation of America, first as a nursing supervisor, then as a hospital executive and eventually as president of the company’s outpatient services group.