Donald Trump has picked JD Vance, a senator from Ohio, to be his vice presidential running-mate for the Republican party, he announced on his social media platform Truth Social on Monday. “I have decided that the person best suited to assume the position of vice president of the United States is Senator JD Vance of the great state of Ohio,” Trump wrote. Vance’s memoir “Hillbilly Elegy” was a bestseller, and although he was once a scathing critic of Trump, he has since wholeheartedly embraced him. Trump made the announcement as the Republican national convention got underway in Milwaukee, Wisco…