Robert F. Kennedy Jr. is Donald Trump’s pick to lead the Department of Health and Human Services in the new administration. The idea of Trump, a Republican, appointing Kennedy to his cabinet would have been surprising just a few months ago. After all, Kennedy began his presidential run last year as a Democrat and is the scion of a Democratic dynasty. Nephew of former President John F. Kennedy and the son of former U.S. Attorney General Robert F. Kennedy, Kennedy spent most of his career as a lawyer representing environmental groups that sued polluting corporations and municipalities. Yet Kennedy, 70,…