MILAN (AP) — More than 4.6 million voters in Sicily are heading to the polls Sunday to pick a new regional governor in the last important vote before a national election early next year.

While five candidates are running, political polling heading into the vote indicated that the race has narrowed down to a contest between center-right candidate Nello Musumeci and the 5-Star Movement's Giancarlo Cancelleri. Both parties hope a victory will give them momentum heading into the national race.

Because of fears of vote tampering, the Interior Ministry in Rome has ordered that no votes be counted until Monday morning

A victory by Musumeci would restore the traditional political order of the island, after four years of a center-left administration. On the other hand, a victory by the 5-Star movement would hand the populist party its first regional administration, and a complicated one with lagging economic growth, high youth unemployment and embedded Mafia culture.

The Sicily vote has turned into a proxy of sorts for national politics, with all the major national party leaders, including former Premier Silvio Berlusconi for the center-right, 5-Star Movement founder Beppe Grillo and Democratic Party leader Matteo Renzi, converging on the island in recent weeks to stump for their candidates.

Musumeci, a former Catania provincial president, has been backed by Berlusconi's Forza Italia, the Northern League and the far-right Fratelli d'Italia, as the center-right seeks to regain control over the island it governed for most of the last two decades.

It remains unclear, however, to what extent a center-right victory in Sicily would consolidate the alliance on a national level with Berlusconi and Northern League leader Matteo Salvini locked in a battle for dominance.

"Although the center-right is running united, the party leaders haven't campaigned together and the key question of the leadership of the alliance remain unresolved," said political analyst Wolfango Piccoli of Teneo Intelligence consultancy.

The 5-Star Movement has made clear it won't enter a coalition with any other party, weakening its chances of running a majority government even if it is the largest vote-getter.

"That would make things even more complicated," said Giovanni Orsina of Rome's LUISS University, noting that 5-Star mayors in both Rome and Turin were facing political difficulties. "Imagine adding to that another complicated situation. I think they would be very happy not to win — to get a very good result, but to lose."

Renzi, who stepped down as premier after a constitutional referendum he staked his political future on failed last December, has been the least visible on the Sicily campaign circuit. Analysts say the risk is that the Democratic Party candidate falls behind that of the far-left. The Democratic Party is becoming increasingly splintered and Renzi has been broadly criticized for such political missteps as his recent opposition to the confirmation of the Bank of Italy governor.

"The left is a nightmare," Orsina said. "Renzi is starting to become a tragic figure, showing how to lose everything in just a few months, from being the center of the electoral system to becoming an electoral liability."