When Silvio Berlusconi put his foot in his mouth yet again last week, claiming that kickbacks are a normal part of doing business abroad, Italy waited for a crushing rebuke from his main opponent in this month's election.

But Pier Luigi Bersani is not a man for the cut and thrust of tough political campaigning and, as usual, failed to deliver the killer blow, managing instead the rather limp sound bite: "Enough with bribes, enough with Berlusconi."

It was no better than Bersani's normal performance in front of TV cameras, where the head of Italy's center-left coalition often looks distracted and uncomfortable. But a lot is riding on him becoming a credible rival to the three-time prime minister as millions of Italians, and even foreign governments, look to Bersani to stop a Berlusconi surge that analysts fear could prompt political paralysis and take Europe and the global economy back to the brink of disaster.