Robert F. Kennedy Jr. walked into his confirmation hearing expecting a grilling. Instead, he gave a master class in Washington’s most predictable theater—politicians masquerading as public servants while performing for their real benefactors. That spectacle, courtesy of Senators Elizabeth Warren and Bernie Sanders, should dispel any remaining illusion that the progressive wing of the Democrat Party is anything but a reliable arm of the medical-industrial complex. Robert F. Kennedy Jr. carries a storied name in Democrat politics, but his break from the party’s establishment is now undeniable. Once part of the liberal political dynasty, he has charted a different course,...