And in Oslo this morning came this announcement of one of the world's most prestigious awards.The Norwegian Nobel Committee has decided that the Nobel Peace Prize for 2015 is to be awarded to the Tunisian National Dialogue Quartetfor its decisive contribution to the building of a pluralistic democracy in Tunisia in the wake of the Jasmine Revolution of 2011.It was Tunisia's Jasmine Revolution that set off the Arab Spring.The organization of civil society groups known as the Quartet was formed in the summer of 2013, after a series of political assassinations threatened to tear that small country apart.NPR's Leila Fadel has covered Tunisia for years, and she joins us now from London. Good morning.Good morning.Tell us more about the Tunisian National Dialogue Quartet.Well, as you said, this is a group of civil society organizations made up of the powerful labor union, the Tunisian Confederation of Industry, Trade and Handicrafts, the Tunisian Human Rights League and the Tunisian Order of Lawyers.And these are groups that sort of touch every part of Tunisian society.And after these political assassinations began, the Quartet stepped in and became the mediator between Islamists and secularistsand really are credited with keeping pluralistic democracy alive in Tunisia.And why the Quartet for this huge, important prize?