It began with a modest remark during a roundtable discussion with reporters: First lady Michelle Obama said she supports making it easier for mothers to breast-feed their babies, because "kids who are breast-fed longer have a lower tendency to be obese."

Within days, the sentence - and a new Internal Revenue Service policy offering tax deductions for breast pumps - had touched off a political firestorm. Rep. Michelle Bachmann (R-Minn.) blasted the Obama administration for trying to impose a "nanny state" on mothers. Another potential 2012 presidential candidate, former Alaska governor Sarah Palin, mockingly said the first lady was trying to compensate for high milk prices. The East Wing withdrew, issuing a brief statement calling the subject "personal."

For Mrs. Obama, the moment is a reminder that she will inevitably become more of a target as the 2012 campaign gets underway. After cultivating a non-controversial image as the "Mom in chief" over the past two years, she remains overwhelmingly popular with the public, yet even her most carefully planned moves will not be immune to political jabs.

But the incident goes well beyond the first lady - raising questions about health policy and the role of government. Should the tax code offer an incentive aimed at working mothers who pump breast milk and not at those who stay home or give their children formula? Are breast pumps any different from other routine medical items that qualify for tax deductions? Is breast-feeding truly better for children?

The discussion has both riveted and dismayed those involved in the breast-feeding issue. "We all expect this - we all know the Republicans and Democrats have their differences," sighed Marsha Walker, a registered nurse who is executive director of the National Alliance for Breastfeeding Advocacy.

Referring to Bachmann, Walker said: "It's not that she's against breast-feeding. It's that she's using it as a vehicle of attack. And it's unfortunate, because breast-feeding isn't a political entity. It's a public-health entity that doesn't deserve to be used as political leverage."

Much of the discussion centers not only around Obama's remarks but also the new IRS rules, which were announced on Feb. 10 and will apply retroactively to devices purchased in 2010 and in the future. The tax authority found that breast pumps "are for the purpose of affecting a structure or function of the body of the lactating woman," thus putting them in the category of a medical device.

Nursing mothers now have two options: If they have a medical flexible-spending account, they can potentially use pretax dollars to buy nursing supplies and breast pumps, which can run as much as $330 or more. Which devices will qualify will depend on each FSA's rules.

If a woman does not have an FSA, she can itemize her taxes and deduct breast-feeding equipment costs, as long as her overall out-of-pocket medical costs exceed 7.5 percent of her income. Only about one-third of taxpayers itemize their taxes. In no case will breast-milk equipment receive a tax credit, the IRS said.

Nor is the federal government purchasing breast pumps for women, as Bachmann claimed. In an interview with conservative radio host Laura Ingraham, Bachmann said she gave birth to and breast-fed five children without government help and described the new policy as part of a liberal agenda.

"To think that government has to go out and buy my breast pump. . . . You want to talk about nanny state, I think we just got a new definition," Bachmann said.

After her remarks drew attention, Bachmann added in a statement: "The issue is not breast feeding, but is rather Washington's use of the tax code to tell people how to run their lives."