Rome, October 12 - Thursday could be a key day for a controversial bill to introduce a new election law. The bill, nicknamed the Rosatellum, is set to be put to a third confidence vote in the Lower House after passing two on Wednesday. It could then face a final test in the Lower House with a secret vote, when it risks being scuppered if lawmakers belonging to groups backing the bill do not following the line of their parties. The anti-establishment 5-Star Movement (M5S) and the left-wing MDP groups both staged protests in Rome on Wednesday against the bill and the use of confidence votes to try to push it through. There is also tension within the ruling Democratic Party (PD) and former president Giorgio Napolitano criticised the confidence move, lamenting the limitations it put on the parliamentary debate and lawmakers' ability for shape the bill. Ex-premier Massimo D'Alema, a member of PD splinter group MDP, blasted the bill as "an unacceptable law, the (PD) leaders are wearing out democracy". Those who attack the ruling centre-left democratic Party (PD) weaken the only "bulwark against populism," PD leader Matteo Renzi said Wednesday, citing as populists the anti-establishment 5-Star Movement, former centre-right premier Silvio Berlusconi and the anti-euro, anti-migrant Northern League (LN). On the PD-led government's controversial use of confidence votes to push through an election-law bill, ex-premier Renzi recalled that postwar Christian Democrat statesman Alcide De Gasperi used confidence votes for key policies.