Former Italian Prime Minister Matteo Renzi

:: Former Italian Prime Minister Matteo Renzi is poised to win the leadership of Italy’s ruling Democratic Party (PD) in a primary election Sunday, propelling him back to the forefront of the national political scene.

Renzi, 42, resigned as prime minister in December after Italians overwhelmingly rejected a constitutional referendum.

A centerpiece of his political platform, the reform had aimed to streamline Italy’s parliamentary system.

In the aftermath of the December vote and facing a rebellion from the left wing of his center-left party, Renzi in February stepped down as party leader with the aim of regaining legitimacy in a future vote.

Renzi faces two candidates considered further to the left: Justice Minister Andrea Orlando and Michele Emiliano, who heads the southern Puglia region.

An internal vote conducted by the party earlier this month suggests Renzi could win hands down: He had more than a majority at 66.7 percent, with 25.3 percent for Orlando and eight percent for Emiliano.

Lorenzo De Sio, a professor of political sociology at the Luiss University in Rome said Renzi’s legitimacy will hinge on voter turnout.

“Rather than a competition, we are facing the legitimization, a sort of crowning of Renzi as leader of the PD. We can expect a huge Renzi victory but with weak voter turnout. People on the left do not seem to be mobilized,” he says.

“If participation rates are around a million people or less, the legitimization of Renzi won’t be strong, if it is between 1.5 and two million, he will wind up in a stronger position,” he adds.

The winner of the vote will lead the party during legislative elections slated for spring 2018 unless parliamentarians come to agreement on electoral reform before then and call for early elections.