By SUZAN FRASER
ANKARA, Turkey (AP) — In the year in which the Turkish republic marks its centenary, the country is being closely watched to see if a united opposition can succeed in unseating an increasingly authoritarian leader in the NATO-member country. Turkey’s presidential and parliamentary elections, taking place on Sunday, could stretch President Recep Tayyip Erdogan’s rule into a third decade — but they could also set the country on a new course. A six-party alliance has got behind the opposition candidate, Kemal Kilicdaroglu, and polls give him a slight lead over Erdogan. But after 20 years in power, Erdogan is unlikely to go quietly.