ISTANBUL—Turkey’s President Recep Tayyip Erdogan took up a new mandate with vastly expanded powers on Monday, and vowed to use his broadened authority to position his nation as a driving force linking East and West—a gambit that will face an immediate test at a NATO summit.
The Turkish leader, who won re-election and secured a majority in parliament last month, took the oath of office before kicking off his new term with a ceremony at Ankara’s sprawling presidential palace.
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