Turkey elections will be President Recep Tayyip Erdogan's biggest test yet. Here's why the world is watching.

Istanbul — Turkey will hold national elections on Sunday that look set to be the toughest test of President Recep Tayyip Erdogan's long political career. After ruling the country for two decades, polls showed Erdogan neck-and-neck with rival Kemal Kilicdaroglu, the candidate fielded jointly by the opposition Nation's Alliance.

Erdogan was applauded during his first decade as leader for transforming Turkey into an economic and political success story, but over the last 10 years he's faced mounting criticism — both domestically and internationally — for quashing dissent and adopting rules and laws typical of autocratic regimes.

Once a poster child for developing nations, Turkey is also currently battling high inflation and a cost-of-living crisis, both of which are regularly blamed by opponents and economists on Erdogan's unorthodox economic policies.