His veto of Savona infuriated the leaders of those parties, who today were talking not about presenting fresh proposals to Mattarella, but rather calling for new elections.
Italian media speculated that, in the meantime, Mattarella could try to appoint a technocratic government. Reuters reported that Carlo Cottarelli, a former International Monetary Fund official, was being summoned for a meeting tomorrow to potentially help lead that effort.
Mattarella said he was protecting Italy's best interests with his rejection and had asked the parties — the far-right League and the anti-establishment Five Star Movement — for a nominee who wouldn't provoke "Italy's exiting of the euro."
"The adhesion to the euro is a choice of fundamental importance for the perspectives of our country and our youth," Mattarella said. "If you want to talk about it, we need to do it openly and with a serious, in-depth analysis."
During recent days, Italian bonds have slumped, raising the country's borrowing costs, and Mattarella said this represented "concrete risks for the savings of our fellow citizens and of Italian families."
Four days earlier, Giuseppe Conte, a little-known academic, had been granted the opportunity by Mattarella to draw up a list of ministers and attempt to form a government.
The parties that chose Conte as premier had spent the previous weeks drawing up a platform for a new government, and although both parties have at times signalled their opposition to the euro, exiting was not mentioned in the final version of their proposed platform.
That platform called for spending that could have potentially raised the country's indebtedness and clashed with European Union fiscal rules. That spooked markets. Italy has one of Europe's highest debt ratios and has dealt for several years with various austerity measures.
"What a bad day for Italy and Democracy," the League's leader, Matteo Salvini, wrote on Facebook. "Everything was set, and I, too, was ready to deal with immigration and security, but someone today said NO. The government of change could not be born; the Lords of [bond] Spread and banks, the ministers of Berlin, Paris and Brussels did not agree. Anger? Lots. Fear? Zero. We'll change this Country, together. I'm not giving up Friends, I'm counting on You. Italians first!"
Five Star leader Luigi Di Maio asked what was the point of voting "if ratings agencies" make the decisions.
The Five Star Movement and the League were the parties that gathered the most momentum from inconclusive March 4 elections, together capturing more than half the vote.
Polls in Italy since indicate that the parties' support has held steady or grown.
But they are gatecrashers in Italy's national politics, and today, former prime minister Matteo Renzi, a member of the Democratic Party, wrote on Facebook that Di Maio and Salvini had taken Italy hostage "for three months."
He said: "They were supposed to govern, but they're fleeing their responsibility: either they aren't capable, or they're afraid."
Renzi added: "In recent weeks they've burnt billions of savings of the Italians, with scatterbrained statements on the euro, on our debt, on the future. And today, instead of jump-starting the government as they could easily have done, they attack the President of the Republic, calling for his impeachment."
