Sen. J.D. Vance (R-Ohio), who was unveiled as Donald Trump’s running mate two days ago, will be in the spotlight Wednesday on the third day of the Republican National Convention in Milwaukee. Vance, a freshman senator and onetime Trump critic who has emerged in recent years as one of the former president’s most vocal and fervent backers, is slated to give a prime-time address. Trump is scheduled to address the gathering of delegates on Thursday.