Roberto Speranza, parliamentary floor leader for the PD in the lower house, said he was stepping down because he disagreed with the government’s approach to the law and believed it was making a mistake.
“I believe in the government, I believe in the PD and the group, but at the moment the difference between the choices made and what I think is too big,” Italian daily La Repubblica quoted him as saying.
Speranza is among several PD dissidents who have opposed Renzi’s proposal for the law, which aims to modify electoral rules after a deadlock at the last national election in 2013 forced the centre-left and centre-right parties to form a weak coalition government.
The resignation will not directly impact Renzi’s governing ability but it is a sign of growing disagreement and rebellion within his party.
Political instability in Italy would also add to the eurozone’s woes, especially amid Greece’s debt renegotiations, and after a period of relative calm in financial markets helped by the European Central Bank’s bond-buying programme.
The electoral law, which would introduce a two-round voting system, has been one of the most heated issues facing Renzi’s government. He has threatened to go to early elections if it is not approved by parliament.
By Catherine Hornby