Robert F. Kennedy Jr.’s failure to install a fellow vaccine critic to a key government post is testing the limits of how far the US health secretary can go to promote his public-health agenda.

Kennedy Jr., an ardent vaccine critic who would have been Weldon’s boss as health secretary. Perhaps Weldon’s biggest problem was that he said the quiet part out loud. During his confirmation hearings,

Republican lawmakers may not have considered avowed anti-vaxxer and conspiracy theorist Robert F. Kennedy Jr. to be too radical to run a federal health agency—but it turns out that Dr. Dave Weldon is.