WASHINGTON (Reuters) - The troubled start of President Barack Obama's signature healthcare law known as Obamacare has administration officials scrambling to address a host of problems, from the unreliability of the website HealthCare.gov to questions about who is responsible for hundreds of thousands of Americans losing their current coverage.
Here are some of the key figures involved in the rollout of the federal health insurance exchange's online portal on October 1 and in addressing criticisms since that time.
PRESIDENT BARACK OBAMA
Obama has been on the defensive about his healthcare policy since October 1, when HealthCare.gov was switched on and crashed the same night, preventing people from going online to create accounts and enroll in health insurance. He has promised the website is just weeks away from a cure, and struggled to convince Americans he is on top of what has become a self-inflicted wound to the signature achievement of his presidency.
While experts have been called in to fix technical glitches, a separate problem has emerged - Obama's pledge that people who are happy with their health plans would not have to change coverage because of the law.
Obama said on October 30 that "bad apple" insurance companies, not his healthcare law, are to blame for hundreds of thousands of people losing their coverage in the past few weeks. Insurance companies say the law requires coverage beyond what many people choose to purchase.
Obama has stood firm against Republican attempts to defund or delay the healthcare law - efforts that led to a 16-day government shutdown in early October.
WHITE HOUSE ADVISER JEFFREY ZIENTS
The administration announced on October 22 that Zients had been brought in to lead a "tech surge" aimed at repairing the website. Three days later, Zients promised that HealthCare.gov would be working smoothly for most users by the end of November, and said a "general contractor" would manage repairs - Quality Software Services Inc, a unit of UnitedHealth Group.
Zients, a former official of the Office of Management and Budget, will become head of the National Economic Council in January. So his assignment as the website's Mr. Fix-It is intended to be temporary.
Zients has 20 years of business experience as a chief executive, management consultant and entrepreneur. He helped the Obama administration figure out a solution for the "cash for clunkers" car exchange program's website, which crashed repeatedly when it opened early in Obama's first term.
WHITE HOUSE CHIEF OF STAFF DENIS MCDONOUGH
McDonough took on a prominent behind-the-scenes role months ago in explaining how Obamacare would work after Democrat Max Baucus, chairman of the Senate Finance Committee, sounded the alarm in April about how few details were being shared with Congress.
Baucus warned of a coming "train wreck" if the administration were to fail to enroll enough people for coverage. McDonough then began briefing Baucus every two weeks on healthcare, and chatting just as often with Health and Human Services Secretary Kathleen Sebelius.
HEALTH AND HUMAN SERVICES SECRETARY KATHLEEN SEBELIUS
As the member of Obama's Cabinet in charge of implementing the Affordable Care Act, Sebelius is facing Republican calls to resign over Obamacare problems.
The former Kansas governor has not resigned, but she has taken the blame for HealthCare.gov's troubled launch.
She also told a House of Representatives hearing on October 30 that the administration did not have any reliable enrollment figures from the website. But a day later, administration papers released by a congressional committee showed that enrollment was very small in the first two days of the website's operation - with just 248 people signing up.
CMS DIRECTOR MARILYN TAVENNER
Tavenner, a former nurse, heads the U.S. Centers for Medicare and Medicaid Services (CMS), which is part of the Department of Health and Human Services and was in charge of setting up the online insurance exchanges. Two months before the administration turned on the website, Tavenner assured Congress that the work was on track.
She got to apologize to Congress for HealthCare.gov before Sebelius.
Sebelius testified that Tavenner made the decision to ask consumers to register on the website before browsing for price information, a step that has been blamed for bottlenecks on the site when it was first switched on.
Tavenner has a lot of fans on Capitol Hill, including her fellow Virginian, House Majority Leader Eric Cantor, a Republican.
CMS CHIEF OPERATING OFFICER MICHELLE SNYDER
Snyder, a veteran CMS official, oversees daily operations at the agency, which has a staff of nearly 5,000. At the October 30 hearing, Sebelius mentioned Snyder when asked to name the person responsible for building the website.
But Sebelius added: "Michelle Snyder is not responsible for the debacle. Hold me accountable for the debacle. I'm responsible."
CHIEF U.S. TECHNOLOGY OFFICER TODD PARK
Park, who previously ran multiple healthcare IT companies, was trotted out over the summer to talk up the launch of HealthCare.gov, but his direct role in the rollout is unclear. House Oversight Committee Chairman Darrell Issa has asked Park and White House Chief Information Officer Steve VanRoekel to supply documents about their involvement in the website.
Park is now part of the administration's "tech surge" to repair the healthcare website.
WHITE HOUSE HEALTH ADVISER JEANNE LAMBREW
Lambrew is a long-term confidante of Obama's on healthcare. An academic and health policy expert, she advised Obama during his first presidential campaign in 2008.
She headed the Health and Human Services Office of Health Reform when the Obama administration was pushing its healthcare overhaul on Capitol Hill.
In March 2011, she moved to the White House as deputy assistant to the president for health policy, a job in which she would oversee White House implementation of Obamacare.
CMS DEPUTY CHIEF INFORMATION OFFICER HENRY CHAO
Chao was part of the CMS team of officials who interacted with contractors building the website. He was one of two officials whose names appeared on a government memo about security concerns dated four days before HealthCare.gov opened. The memo said the website was at "high risk" because of lack of testing.
Chao said at an insurance industry meeting in March that he was "pretty nervous" about the exchanges being ready by October 1, adding, "let's just make sure it's not a Third World experience."
HHS CHIEF TECHNOLOGY OFFICER BRYAN SIVAK
Sivak joined the Department of Health and Human Services in July 2012 to help the agency harness the power of technology to improve healthcare. He has appeared numerous times at conferences about bringing the mentality of startup tech companies to the federal government.
Sivak's name surfaced in documents released by Issa's committee October 29, showing he and another HHS employee brushed aside offers of help with the stuttering website from Amazon Web Services Inc.
The papers showed an employee of Amazon Web Services emailed Sivak and another HHS official on October 7, saying, "I hear there are some challenges with Healthcare.gov. Is there anything we can do to help?"
Sivak replied in an email the next day: "I wish there was. I actually wish there was something I could do to help."
(Reporting By Susan Cornwell; Editing by Karey Van Hall and Mohammad Zargham)