Guest host: Lee Cowan. In our cover story, Robert Costa reports on the changing dynamics of the presidential race. Also: Martha Teichner looks at the rise of Vice President Kamala Harris to presumptive Democratic Party nominee; Jo Ling Kent talks with “Wicked” director Jon M. Chu; Seth Doane explores the secrets surrounding the graffiti artist Banksy; Lee Cowan interviews Ralph Macchio, whose character in the 1984 movie “The Karate Kid” is featured in the popular Netflix series, “Cobra Kai”; Ramy Inocencio examines the changes in Hong Kong since the passage of new laws aimed at suppressing political protests; and Conor Knighton watches the creation of meditative “sand circles” on an Oregon beach that are drawing crowds.