 This was the first rally that Donald Trump and his vice president pick, J.D. Vance, have done together. It's also significant because it was in Michigan, a key battleground state. J.D. Vance, who has written about growing up in poverty, is seen by his party as someone who can appeal to crucial working class voters in swing states. The mood was buoyant and confident. Donald Trump painted the Republican Party as united, describing last week's convention as a big, beautiful four-day love fest.