Why did Alexis Tsipras call a referendum in July 2015?

In June 2015, Prime Minister Alexis Tsipras called for a national referendum on the terms of the debt crisis bailout to secure a stronger mandate for his negotiations with the troika (Greece's creditors).12

Tsipras sought to use the referendum as a tool to gain leverage, aiming to negotiate better bailout conditions rather than simply accepting the terms previously offered. He explicitly urged Greek voters to reject the proposed terms by voting "no," framing the referendum not as a choice regarding Greece's continued participation in the euro zone, but as a means to strengthen his position in seeking more favorable terms.1

Following the overwhelming "no" vote on July 5, 2015, Tsipras ultimately had to navigate the threat of financial collapse and potential "Grexit." He subsequently presented a new reform proposal to creditors and, despite internal party opposition, secured a new bailout agreement that he characterized as a deal he did not believe in but was obliged to implement to prevent economic catastrophe.12