Reuters has a detailed report on the final deadline to sign up for Obamacare, and how we got here:

Tuesday is a moment of truth for Obamacare.

It marks the final deadline for most Americans to sign up for health insurance under President Barack Obama’s 2010 Affordable Care Act, popularly known as Obamacare, if they want coverage starting on January 1.

If enough people – and the right mix of young and old – do not enroll, the ambitious program designed to provide health benefits to millions of uninsured and under-insured Americans risks eventually unraveling.

Unraveled. There’s that word again. What a great title for a book.

The article has some discussions of the role Marilyn Tavenner played:

Tavenner’s anxiety – more than a year ahead of the planned launch of the exchanges – spurred concerns among industry and advocacy groups, which publicly questioned whether the multiple government agencies involved in the effort would be able to pull it off.

The White House was closely briefed on the issues. Tavenner was cleared to visit White House officials involved in the project 425 times from December 2009 to June 2013, including several meetings with Obama, visitor logs show. The White House said later that Obama knew only the broad picture, not details of the effort.

The administration also sought industry feedback, but some groups complained their warnings fell on deaf ears.

And detailed records of when people in the Administration, including POTUS, knew about possible problems:

Tavenner assured the panel that software development and testing for HealthCare.gov would be done by September 2013.

A week later, on April 18, Tavenner’s boss, Katherine Sebelius, secretary of Health and Human Services, delivered a similar message to a House budget panel. She said work on the insurance exchanges was “up and running, and we are on track.”

These confident public displays masked a different reality.

Earlier that month, Tavenner and Sebelius had been briefed by an outside consultant about a broad array of risks threatening the October 1 launch of HealthCare.gov.

The report by the consulting firm McKinsey & Co depicted a tangled, leaderless bureaucracy managing the effort and warned of possible system failures that materialized barely six months later. It blamed tight deadlines, insufficient testing and the absence of a “single, empowered decision-making authority.”

The report sounded the alarm. Attendees at high-level briefings that followed included Todd Park, the White House chief technology officer, and Brian Sivak, the HHS technology whiz brought in to jumpstart health technology systems.

The consultants met with Tavenner and Jeanne Lambrew, Obama’s healthcare adviser who, two decades earlier, had worked on a failed healthcare overhaul spearheaded by then-first lady Hillary Clinton.

Obama also was briefed on McKinsey’s findings, White House press secretary Jay Carney later acknowledged. White House logs show two McKinsey consultants arriving for a meeting on April 8, but the company would not comment on the visit.

The first public hints of official concern about possible problem’s with Obamacare’s technology actually came on March 22 – before Tavenner and Sebelius had expressed their confidence to Congress and just as McKinsey’s findings began to make their way through the administration.

And then things fell apart:

Chao wrote to colleagues on July 16 to say that he feared CGI could “crash the plane at takeoff,” according to e-mails released by Republican congressional investigators. CGI has declined to comment.

Alarming assessments streamed in from CMS technical advisers.

“We believe that our entire build is in jeopardy,” wrote one, referring to the elaborate website construction.

E-mails flew back and forth between Chao and the contractors until a CGI vice president assured Chao, “I am on top of this.”

For Chao, meeting the October 1 deadline to have the website functioning well had become a matter of personal honor. Along with Tavenner, he had given sworn testimony to a congressional committee and assured skeptical members that the agency was on track.

On July 20, Chao urged his staff to redouble its effort and sent a link to his testimony.

“I wanted to share this with you so you can see and hear that both Marilyn and I, under oath, stated we are going to make October 1,” Chao wrote. He urged them to “put yourself in my shoes” and help him make those words the truth.

And five days before the deadline, the site crashed with 500 simultaneous users:

At CMS, system tests during the third week of September were “not good and not consistent at all,” one employee told Chao in an e-mail. At a time when the website should have been able to accommodate 10,000 simultaneous users, it was crashing with 500 simulated users on it – about a week before the site’s scheduled launch. Contractor CGI called the glitches “part of the tuning exercise.”

Chao shot off an all-caps message to his staff, ordering that tests continue, just five days before the deadline.

At the White House, technology officer Park questioned Chao about the website’s progress. If Park sensed disaster, he gave no hint.

“Massive kudos again for the incredible progress the team is making!” Park wrote in an e-mail.