Italian Prime Minister Matteo Renzi resigned Wednesday after nearly 60 percent of voters rejected a referendum Sunday on a series of changes to the constitution that Renzi had staked his premiership on. The referendum’s failure and the resignation of the brash prime minister have plunged Italy into political and economic uncertainty, leading many to speculate about Italy’s future in the eurozone and the strength of populist movements across Europe.

Renzi said the constitutional reforms would make Italy a more governable country by reducing the size and power of the Italian Senate, the upper house of parliament, and empowering the lower house, the Chamber of Deputies. But for many Italians, the referendum was a way to air their grievances with Renzi and his coalition’s failure to deliver on campaign promises, including reducing unemployment and increasing economic growth. ...