The so-called "ius soli" bill, which would create an earlier path to citizenship for children of foreign parents born and schooled in Italy, is one of the centre-left government's key proposals but has languished in the senate for months amid fierce opposition from the right.
Now the governing Democratic Party (PD) has definitively given up on passing the reform before Italy's general election, which is expected in early March.
The bill is scheduled to be put to a vote only after parliament has agreed on lengthy budget proposals, the PD's senate whip said on Wednesday, effectively ending the chances that senators will vote on citizenship reform this parliamentary term.
"At the moment we don't have the majority to approve it," said whip Luigi Zanda, explaining that passing the ius soli bill would require a confidence vote that could topple the PD's coalition government in the final months of its term. "That's a risk we can't take," he said.
The PD's junior coalition partner, the centrist Popular Alternative (AP) party, has opposed the citizenship reform, along with Silvio Berlusconi's centre-right Forza Italia party, the far-right Northern League and others.
The League in particular has sought to link the proposed reform with the migration crisis that has seen thousands of people arrive in Italy – even though the bill has little to do with new arrivals.
The new law would lower the age at which people born in Italy to non-Italian parents can apply for citizenship, from 18 to between 10 and 12. Only children who have spent at least five years in Italian schools would be eligible.
The Democratic and Progressive Movement (MDP), which supports the bill, accused the government of "throwing in the towel" on what was supposed to be one of its signature reforms.
Several members of the PD, including Interior Minister Marco Minniti, reaffirmed their support for ius soli. Senator Luigi Manconi, who went on hunger strike this week to demand action on the bill, said that he and other supporters would continue to seek a vote before parliament is dissolved for the election.