Leo Barraclough International Features EditorIn a presentation delivered to buyers this week during the virtual American Film Market, the stars of biopic “McCarthy,” Michael Shannon and Emilia Clarke, as well as its director Václav Marhoul and screenwriter Tom O’Connor, explained why the story of the venomous demagogue Joseph McCarthy had to be told now.The film, now in development, follows McCarthy’s journey from being an ambitious Republican Senator to the most powerful and feared man in the