For the first time in modern American history, a skeptic of medical research could be responsible for safeguarding public health.

While Mr. Kennedy, seeking the job of health secretary, has been vocal about vaccines and his desire to overhaul the nation’s diet, he has said very little about other issues.

If approved, Kennedy will control a $1.7 trillion agency that oversees food and hospital inspections, hundreds of health clinics, vaccine recommendations and health insurance for roughly half the country.

Robert F. Kennedy Jr.’s anti-vaccine advocacy is outside the mainstream. His previous statements on abortion could alienate Republicans. But a new poll finds that not all of his controversial health goals are unpopular — in fact,