Italy's Renzi says his political future hinges on 2016 referendum
Renzi has attached considerable political capital to a bill which he says will make the country more governable.
It will reduce the number of senators by two-thirds and strip the Senate of its ability to bring down a government and sharply limit its scope to block legislation.
Because it involves a change in the constitution, the bill, which is currently going through parliament, will have to be put to a referendum. It is expected to be held in October.
(Reporting By Philip Pullella)