Robert F. Kennedy Jr. is poised to have an influential role in the next Trump administration as the president-elect's pick to lead the Department of Health and Human Services. Recently, Kennedy told news outlets that a top priority will be directing communities to take fluoride out of their drinking water. Fluoride has been a pillar of public health for decades, and the Centers for Disease Control and Prevention describes it as one of the 10 greatest public health achievements of the 20th century. Experts point to evidence that it strengthens teeth and improves oral health. But fluoride has also inflamed local debates, where some oppose the government putting something in public drinking water. Recent research also raises questions about potential benefits and harms of fluoride.Yet these growing debates are already well underway in Oregon, which is home to Portland, the largest U.S. city without fluoride in its drinking water. The liberal suburb of Hillsboro and the small conservative town of Lebanon may also foreshadow the impassioned fights that could soon spread across the country. Whether to add or remove fluoride from drinking water was on the ballots in both places this month, fueling intense battles in person and online. National health reporter Fenit Nirappil recently traveled to Oregon to understand up close the science and politics of fluoride. He spoke with host Elahe Izadi about what he learned. Today’s show was produced by Elana Gordon, who also contributed reporting. Sabby Robinson contributed production help. It was edited by Reena Flores, with help from Lucy Perkins, and it was mixed by Justin Gerrish. Thanks to Tracy Jan. Subscribe to The Washington Post here.You can also read the oral history of Elphaba ahead of the opening weekend of the movie, Wicked, here.