Senator Bill Cassidy deftly grilled Health and Human Services Secretary Robert F. Kennedy Jr. in a Senate hearing Thursday, forcing Kennedy to contradict himself on the topic of vaccines. Cassidy, who chairs the Health Committee, is a Republican and a medical doctor. He’s had to walk a fine line when it comes to Kennedy, who holds many views not based in scientific fact. Cassidy wavered on confirming Kennedy, before ultimately casting a key vote in his favor after securing promises from the