The Pro-EU Premier’s nickname is II Rottamatore - The Demolition Man - but many fear this moniker may come back to haunt him and he could become the main target for his own demolition.
Renzi’s departure would be taken badly by markets that have backed his reform agenda.
Guntram Wolff, director of Bruegel, an influential Brussels-based think tank, said: "Political instability would indeed cause financial instability.”
If his proposals are defeated, opposition parties who are determined to push forward a breakaway from Brussels, and with Brexit increasing anti-EU sentiment across the continent, they will prepare for a fight to topple the union.
The autumn vote is about major constitutional change to Rome's notoriously slow and costly system of government.
Italy is one of EU’s founding members, with the union’s flag standing proud atop state buildings nationwide.
However, the ongoing migrant crisis and the bloc’s failure to stop thousands arriving on the nation’s shores, as well as constant negotiations over its finances, has left many Italians scorned.
Britain’s momentous decision to sever ties with Brussels was celebrated by anti-establishment and Eurosceptic party the Five Star Movement.
Five Star Movement, founded by comedian Beppe Grillo, has now become the most popular party in Italy after it won a quarter of the national vote in 2013 and last month clinched the mayoral seats in Rome and Turin.
Recent polls show it has 30.6 pr cent of the vote - up from the ruling Democratic Party’s 29.8 per cent.