Lobbyists in Washington say they are being flooded with questions and concerns from foreign governments about the rise of Donald Trump. Officials around the globe are closely following the U.S. presidential race, to the point where some have asked their American lobbyists to explain, in great detail, what a contested GOP convention would look like. The questions about Trump are “almost all-consuming,” said Richard Mintz, the managing director of Washington-based firm The Harbour Group, whose client list includes the governments of Georgia and the United Arab Emirates. After a recent trip to London, Abu Dhabi and Beijing, “it’s fair to...