WASHINGTON (CNN) -

Shortly after Kathleen Sebelius was tapped to carry out President Barack Obama's signature health care reform effort, the head of Health and Human Services found herself in the crosshairs of Republicans determined to repeal the law.

The two-term Kansas governor-turned-Obamacare-chief-defender is resigning as health secretary. She's leaving after a problem-plagued rollout of HealthCare.gov, the federal website portal critical to the law's implementation, but with the administration taking a victory lap after unexpectedly reaching and then exceeding its sign-up target of 7 million.

A tweet by David Axelrod, former senior adviser to Obama, perhaps best sums up the tension Sebelius faced as she tried to navigate implementing the controversial law familiar as Obamacare.

"When all is said and done, Sebelius has lots to be proud of including the surprisingly strong finish on exchange signups after a rocky start," Axelrod wrote.

That sentiment is "a little passive aggressive," said Ryan Lizza, a CNN political commentator.

"They want the message to be: blame Sebelius with the problems with Obamacare especially as they go into a midterm election where this is going to be a big issue. I think that's a little unfair to her."

It wasn't always this way.

She once was seen as a Democratic Party rising star when she was tapped to deliver the Democratic response to President George W. Bush's final State of the Union address.

She was the Midwestern girl whose political blood ran blue but flourished in a red state. Her father was a former Democratic governor of Ohio.

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Former health secretary tapped to carry out president's health care reform effort