Market jitters over whether Italy is heading for a default that would probably destroy the euro have been aggravated by uncertainty over what will happen when respected technocrat Prime Minister Mario Monti steps down for elections next spring. 

Those worries are compounded by confusion over what electoral system will be used, with time running out for politicians to keep years of promises to replace the law.

  The remarkably resilient "porcellum" or pigsty law was passed in 2005. It robs the electorate of the power to choose candidates directly, voting instead for a fixed list selected by party leaders under a proportional system. 

This enables the leaders to select compliant party hacks or favorites, including in the case of Silvio Berlusconi a former starlet who became a minister in his last government.

  The law also awards a large premium to the winning party or coalition, guaranteeing a strong majority in parliament. 

Even the man who introduced the law, the separatist Northern League's Roberto Calderoli, called it "crap" soon afterwards.