The former vice president of Susan G. Komen for the Cure has written a blistering insider’s account that criticizes both sides in the cancer charity’s decision last year to halt grants to Planned Parenthood and its swift retreat in the face of an intense, widespread backlash.

Karen Handel’s book “Planned Bullyhood,” due out Sept. 11, depicts Planned Parenthood as an aggressive, partisan organization that was willing to weaken Komen to further a liberal political agenda.

However, Handel — a conservative who resigned from Komen after its reversal — also assails its leadership as indecisive, timid and politically naive. She calls the hasty decision to backtrack “a terrible mistake.”

Komen hired Handel as vice president for public policy in April 2011 after she lost a Republican gubernatorial primary in Georgia, and gave her the task of figuring out how to disengage Komen from Planned Parenthood. Komen’s grants were for breast-cancer education and screening, but it was under increasing pressure from anti-abortion groups and religious conservatives to cut all ties because Planned Parenthood is the leading U.S. provider of abortions.

Roman Catholic bishops criticized Komen for maintaining those ties, and the publishing division of the Southern Baptist Convention recalled pink Bibles it had sold because some of the money generated for Komen was being routed to Planned Parenthood.

Late in 2011, Komen halted the grants, $680,000 that year, but the decision did not become public knowledge until Jan. 31.

Reaction was immediate and passionate. Twitter and Facebook were flooded with denunciations. Democratic members of Congress and some of Komen’s own affiliates urged it to reconsider. Planned Parenthood accused Komen of bowing to right-wing bullying and mobilized its supporters, raising $3 million in donations within days of the news report.

Handel says Komen’s leaders hoped during December and January that Planned Parenthood would agree to an amicable split and not go public with any angry reaction. However, Handel writes that she became worried about possible leaks to Planned Parenthood from Komen employees or consultants, and says she began to sense that things would end badly for Komen.

“Planned Parenthood would play the victim, accusing Komen of being bullies and succumbing to political pressure,” she writes. “I felt in my heart of hearts that Komen would not have the fortitude to see this through … and somehow knew that I would be the scapegoat.”

Handel says she urged Komen’s president, Liz Thompson, and CEO and founder Nancy Brinker, to hold firm and ride out the firestorm, but Komen announced on Feb. 3 — just three days after the initial disclosure — that it was restoring Planned Parenthood’s eligibility for grants.

Handel, who resigned the next week, was distraught, and says she perceived herself being made the scapegoat for a public-relations fiasco.

“I was upset with myself for not better anticipating how Planned Parenthood would attack. I was angry at what I believed was betrayal by my Komen teammates and our own consultants. And I was deeply disappointed that Nancy had not had the courage to stand up for Komen and what she knew was the best decision for the organization,” Handel writes.

In Handel’s view, Brinker was a strong-willed leader, but “very vulnerable to criticism, especially in the press.” Liz Thompson, according to Handel, was knowledgeable about breast cancer, but “sometimes seemed a bit out of her depth” as Komen president.

Komen announced Aug. 9 that Thompson was leaving and Brinker would relinquish her role as CEO.

Komen spokeswoman Andrea Rader said she could not comment on Handel’s book before its release, but defended the two women who led the charity during the controversy.

“The record is well-known: Nancy Brinker and Susan G. Komen for the Cure have done more for women facing breast cancer than any other individual or organization,” Rader wrote in an email. “Liz Thompson is one of the most highly respected leaders in women’s health in the nation, if not the world.”

A Planned Parenthood spokesman, Eric Ferrero, also said he couldn’t yet respond to specifics in the book, but added in an email, “It is incredible that there are people who still want to inject politics into breast cancer detection and treatment.”