(CNN) The occupant of the Quirinale, the presidential palace in Rome, is meant to be above the daily cut and thrust of politics. Sergio Mattarella has been the model of restraint in his three years as President -- until now.

Mattarella, a 75-year-old Sicilian and veteran politician, is known as a man of few words. But those he spoke Sunday night have sparked a constitutional crisis and populist outrage. He rejected a key appointment in the Cabinet of Prime Minister-designate Giuseppe Conte: that of euroskeptic Paolo Savona as finance minister.

And he was blunt about the reason. "The uncertainty over our position in the euro alarmed Italian and foreign investors," Mattarella said. The rising price of Italian debt would burn through savings and hurt companies.

"Membership of the euro is a fundamental choice for the future of our country and our young people," the President added.

Giuseppe Conte addresses journalists after a meeting with President Sergio Mattarella on May 23.

The man who once described his job as that of a "political referee" was brandishing the red card, and Italy entered its 84th day without a government.

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