“Don’t you want a president who’s going to make America healthy again?” Robert F. Kennedy Jr. asked a roaring crowd, during Sunday’s triumphal rally in support of Trump at Madison Square Garden. When Kennedy, the country’s most famous anti-vaccine activist, suspended his campaign to endorse Donald Trump, it not only represented the death of his presidential aspirations, but the dawn of something new: the so-called “Make America Healthy Again” movement, a tidy bit of sloganeering designed to highlight where Trump and Kennedy’s agendas overlap.