Turkish President Recep Tayyip Erdogan is declaring victory in the contentious national referendum that could keep him in power until 2029 with vastly expanded powers, reports the Washington Post. The apparent victory isn't exactly clear cut, with the opposition not even waiting for the ballot count to finish before declaring they would contest at least 37% of the vote, citing "problematic votes." But with 98% of the vote counted, Erdogan had 51.3% in his "yes" camp, reports the BBC, with about 48.7% voting against. Erdogan supporters are setting off celebratory fireworks in Istanbul, reports the AP, while the president himself is reportedly calling allies to congratulate them on the victory. Here's a primer on what's at stake in the referendum. (More Recep Tayyip Erdogan stories.)