Voters in Portugal go to polls Sunday ; campaign dominated by economic issues . So , ahead of the polls , CNN invited the country 's six leading parties to take part in a social media debate . CNN 's 15 CNN have challenged candidates to answer tough questions . Debate takes the form of a series of billions second Instagram videos . CNN 's Merkel says project could offer glimpse of political discussions of the future .
Voters in Portugal go to polls Sunday ; campaign dominated by economic issues . CNN 's 15 CNN have challenged candidates to answer tough questions . Debate takes the form of a series of billions second Instagram videos . CNN 's Merkel says project could offer glimpse of political discussions of the future .