Pavoncello said the court's decision also makes it highly unlikely, if not impossible, that new elections could be held this year, as some parties would like, thereby securing Monti's technical government until 2013. "It basically says we are going to vote in the spring of 2013, and Monti is going to be there until then," Pavoncello said.

The scenario provoked a vitriolic reaction to the decision from Antonio Di Pietro, a former prosecutor whose Italy of Values party was a main sponsor of a referendum seeking a more representational system. Di Pietro has refused to give the Monti government blanket support, saying his party would vote issue by issue. "There is nothing legal or constitutional about this decision ... (it is) political, to do a favor for the head of the state, to the forces of politics and the majority in Parliament," Di Pietro said in comments posted on his party's website.

The comment drew an immediate response from the office of President Giorgio Napolitano — the head of state — calling it "a vulgar insinuation that was completely gratuitous." Mario Segni, one of the sponsors, said that Italy called it a "political and not legal decision," and expressed concern the issue would be put on the backburner.

"Italy had a chance to rid itself of one of the worst laws that has ever been approved. Unfortunately, the court didn't know how to resist pressure from a political world that considered the referendum an unnecessary disturbance."

In Italy, a referendum may do away with existing laws, not create new ones. Pavoncello said the court may have felt that the referendums would have had the effect of writing a law, which would be against the constitution.