Gabrielle Rifkind operates in the shadows, in the quiet, dark, back rooms of international politics. A bit paradoxically, the 71-ish Londoner strikes a sharp pose: outré pantsuits, dresses. Cool, kooky glasses. A white shock of bobbed hair. Upon meeting her, you really want to talk to her. Which is perhaps the point: The peacemaking organization Rifkind founded in 2016—the London-based Oxford Process—is all about facilitating dialog.