Sen. Bill Cassidy (R-La.) accused Health and Human Services Secretary Robert F. Kennedy Jr. of lying to him in order to get his confirmation vote — particularly on vaccinations, despite Kennedy's clear stance against them — saying Sunday that "the American people have been poorly served" by the secretary.

A physician, Cassidy has been a fierce criticof the Trump administration's position on vaccines, calling the most recent executive order on spacing out childhood immunizations and breaking up the measles, mumps and rubella vaccine a "stupid policy" not rooted in science.

"If it wasn't so potentially tragic, you would break out laughing," the Republican toldCNN's "State of the Union." "It is wrong on so many levels."

Cassidy was confronted by Martha Raddatz on ABC's "This Week" about his decision to vote to confirm Kennedy, a known vaccine conspiracy theorist, to be the nation's top health official. The senator said his choice came from a place of both believing Kennedy's and the White House's guarantees to not touch science-backed vaccine guidance, and of hearing his constituents' concerns about ultra-processed foods.

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"The point is that when you're marking the decision process, you're taking in everything at once," Cassidy said. "And you just make the best decision that presents at the time."

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