 Late this afternoon, the internet was flooded with articles entitled, Who is J.D. Vance? Because J.D. Vance is Donald Trump's running mate. Mr. Trump announced that the Ohio senator and author of Hillbilly Elegy was his pick as Republicans gathered in Milwaukee for the party's national convention and just days after an attempt on Mr. Trump's life. Ohio's delegation immediately began chanting J.D. on the convention floor. Utah Senator Mike Lee also celebrated.