Jovana Gec, Associated Press Jovana Gec, Associated Press BELGRADE, Serbia (AP) — Serbia's populist strongman Aleksandar Vucic dominated the Balkan country's politics for 14 years. Then came the students. The long-ruling authoritarian leader on Sunday conceded the defeat of his right-wing Serbian Progressive Party to a grassroots movement of university students in a parliamentary election. The students had led protests for almost two years before unseating him in a historic change of government.