Susan G. Komen for the Cure continues to be a cautionary tale about the toxicity of our politics, and how easy it is for those politics to drive a large and trusted charity into a ditch.

A movement is forming to pressure the nonprofit’s founding CEO to resign, to walk away from the organization she founded 30 years ago in memory of a sister who died of breast cancer. Nancy G. Brinker is why pink now symbolizes breast cancer awareness and why Komen is a stellar model of fundraising and marketing savvy, raising more than $350 million annually.

In the wake of Komen’s unpopular decision to defund Planned Parenthood, and its subsequent hasty reversal of that policy, several key executives for the Dallas-based charity, including the head of its important New York affiliate, have announced plans to leave. Moreover, the New York affiliate has shelved plans for an annual fundraising gala, likely in fear of a disappointing turnout. Other affiliates are expecting similar difficulties.

Komen’s Planned Parenthood debacle was a textbook example of weak leadership. It began with outside agitators pitching a battle that had nothing to do with stopping the 40,000 deaths to breast cancer that occur every year. And it ended when a partisan operative was given a key role in the organization’s management — and used it to advance a divisive political agenda.

The agitators in question include Catholic bishops, Republican politicians and conservative pressure groups that have long regarded Planned Parenthood as Public Enemy No. 1. According to a report by Reuters, some 23 Catholic dioceses have publicly questioned the morality of supporting Komen due to its funding of Planned Parenthood’s breast cancer outreach programs. (Those programs serve mostly poor women and do not fund abortion or stem-cell research, according to Planned Parenthood.) Ohio’s 11 bishops banned parishes from raising any funds for Komen, and the North Dakota Catholic Conference “cautioned its nearly 190,000 parishioners against donating to Komen,” according to Reuters.

Interestingly, Catholic organizations, including some in Ohio, continued to accept Komen funds.

A year ago, Komen hired Karen Handel as its vice president for public policy. Handel, an unsuccessful Republican candidate for the governorship of Georgia, had made public avowals of her hostility to Planned Parenthood. According to many accounts, it was Handel who engineered the policy change that culminated in the Jan. 31 announcement that Komen was severing its funding relationship with Planned Parenthood.

Komen couched its decision in a new policy that withheld funding from any organization under government investigation. Planned Parenthood wasn’t under formal investigation, although U.S. Rep. Cliff Stearns, a Florida Republican, as chairman of a Energy and Commerce subcommittee was conducting oversight into how the organization used federal funds.

That weak pretext appears to have been Komen’s basis for its disastrously foolish decision.

Within days of that decision, Komen reinstated Planned Parenthood, Handel resigned, and various Komen executives beat their breasts and mumbled their mea culpas. That’s not enough.

As is the case with millions of other Americans, breast cancer has touched my life, in the death of a dear friend’s wife to the disease and the scares of friends and family members who found lumps, both benign and malignant. I’ve run in the local Komen affiliate’s Race for the Cure, and I readily reach for pink golf balls, baseball caps, water bottles and other items when a portion of the sale goes to Komen. Even the dog has worn a pink handkerchief around her neck.

Komen made a big mistake in bowing to political pressure to carry water for someone else’s cause. I need to know that will not happen again, and I’m not alone. A lot of good will and dollars are in danger of evaporating.

Past criticisms leveled at Komen — that it is too large and dominant in the breast cancer cause, that it is insensitive in asserting its claims to ownership of pink ribbons and the slogan “for the cure,” among other unfortunate traits — only add to the impression that Komen has lost its way.

And that’s a shame, because there’s a lot to love — and, hopefully, to salvage — in this exemplary organization.

Mary Sanchez is an opinion-page columnist for The Kansas City Star. Readers may write to her at: Kansas City Star, 1729 Grand Blvd., Kansas City, Mo. 64108-1413, or via e-mail at msanchez@kcstar.com.