Italy's parliament on Thursday passed a controversial law set to disadvantage the Five Star Movement (M5S), the country's newest populist party, in elections expected sometime before March 2018.

The upper chamber Senate voted 214-to-61 in favor of the "Rosatellum" law. Under the law, around one-third of lawmakers will be directly elected to represent a constituency and two-thirds indirectly elected based on a proportional formula.

The Rosatellum will also introduce two separate thresholds for parties to enter the parliament. Single parties will need at least 3 percent of the national vote to get in, whereas multiple parties standing as a coalition will need to get at least 10 percent of the vote.

Read more: Italy's populist 5-Star Movement shakes up politics with election win in Rome

Aligned against the stars?

Supporters of M5S, the main opposition party to the Democratic Party (DP)-led government, took to the streets to protest the Rosatellum. M5S leaders, who have ruled out ever entering a government coalition, said it unfairly penalizes single parties by encouraging coalitions.

"The scam electoral law is like a slot machine," M5S Senate leader Giovanni Endrizzi said. "You press a button, you think you're choosing but there's software that decides for you and eats your money. Here they eat your votes."

Epressing the movement's anger, M5S lawmaker Danilo Toninelli gave the electoral law the Latin-sounding name "Merdellum," which is similar to the Italian word for excrement.

PD Senator Andrea Marcucci admitted the new electoral system was imperfect, but called for pragmatism. The Rosatellum was, he said, "not the best election law in absolute terms, but the best possible that can be passed by parliament."

Renato Brunetta, a lawmaker from former Prime Minister Silvio Berlusconi's party, Forza Italia (FI), lauded the passing of the bill.

"We have done something positive for our country in a moment when political clashes — particularly due to the M5S, which is only capable of protesting and not proposing — show no sign of abating," he said.

Who will rule in Rome in 2018?

Recent election polls predict a center-right coalition including FI and the Northern League winning the most seats under the new system. The coalition is forecast, however, to fall short of winning enough seats to form a majority government. PD is predicted to come in second and M5S third.

Many observers expect the center-right coalition and the PD to form a "grand coalition" in the event that no party attains a majority of seats.

Renato was optimistic that his party would send someone to the prime minister's office after the election. "Next, in 2018, will be our return to Palazzo Chigi. We're ready," he said.

The Rosatellum's adoption will make it easier for Italian President Mattarella to dissolve the current parliament before the end of 2017 and initiate new elections sometime before March 2018.

Relief and anger

Electoral reform has troubled lawmakers in the Mediterranean country in recent years. Problems associated with previous reform efforts had caused the Constitutional Court to intervene, which in turn had led to new problems.

Despite those troubles, M5S has said it will call on Mattarella to veto the law and challenge it at the Constitutional Court.

amp/kms (dpa, AFP)