(Bloomberg) -- The break-up of Italy’s center-left coalition only days after being formed has allowed its center-right opponents to extend their lead, a poll showed. 

The right-wing alliance, led by Giorgia Meloni’s Brothers of Italy and also including Matteo Salvini’s League and Silvio Berlusconi’s Forza Italia, now has 48.2% support compared with 46% before, according to a poll by Quorum/YouTrend for Sky TG24 shows

The center-left union was supposed to help counter a landslide victory by right-wing parties in general elections set for Sept. 25. It broke up over the weekend when Carlo Calenda’s centrist Azione party chose to leave its alliance with the Democratic party.

That leaves the right in a strong position, with the Brothers of Italy in first place among voters with 24.2% backing. Without Calenda’s party, the center-left coalition has slipped to about 29% from 33%. 

Such results raise the possibility that the center-right is set to secure a two-thirds majority in parliament -- enough to change the constitution. That would be unprecedented in Italy’s history and could have a profound impact on the political system if the winners decided to change how the president is elected or how much power the prime minister holds.

All three leaders of the right-wing alliance have called in the past for the president to be elected directly by Italians, instead of by lawmakers and regional representatives, as is currently the case. 

Even in a scenario where Azione teams up with former Premier Matteo Renzi’s Italy Alive party, the right-wing coalition would have 49% support, the poll showed. In that case, the left-wing bloc would get 27.4%.

A separate study by Istituto Cattaneo published Tuesday shows the center-right receiving 46% of votes, allowing it to hold 61% of seats in the Chamber of Deputies and 64% in the Senate.

Istituto Cattaneo said further gains by the right are unlikely based on their analysis of electoral colleges, meaning the center-right would score a landslide victory but probably fall short of the two-thirds threshold.

(Adds Istituto Cattaneo study in last two paragraphs, details throughout.)

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