As U.K. Prime Minister Theresa May presses on to take Britain out of the European Union, one leading economist raised questions about the viability of the single political and economic bloc. “You have to wonder about the future of the European Union itself ... this is an imperfect union and the survivability of it is, I think, a serious question,” Stephen Roach, a senior fellow at Yale University, told CNBC’s Sri Jegarajah on Friday. Even before Brexit came about, the EU faced multiple challenges over the last decade, said Roach, who’s a former chairman of Morgan Stanley Asia. Those challenges include a sovereign ... (full story)