Welcome back to World Brief, where we’re looking at changing United Nations leadership, new doubts over U.S.-Iran peace talks, and Japan ’s massive defense export overhaul. Replacing Guterres It is time to choose who will next lead the United Nations. On Tuesday and Wednesday, four candidates vying to succeed U.N. Secretary-General António Guterres will be grilled on several pressing global issues , from ongoing conflicts to climate change, as well as on how they envision reshaping the