Just days after launching a new political action committee, former Democratic Vice President Joe Biden will join Republican officials and donors at a weekend retreat hosted by former GOP presidential nominee Mitt Romney. Biden will be interviewed by Romney during a Friday evening event in Park City, Utah, at the invitation-only summit, according to a Biden spokesman and participants briefed on the schedule. The speaker lineup for what is traditionally a gathering of Romney allies is packed with high-profile Republicans, among them House Speaker Paul Ryan and Sens. Lindsey Graham and John McCain. Ryan was Romney’s running mate in 2012....