(CNN) -- Little more than a year after he resigned in disgrace as prime minister, Silvio Berlusconi is campaigning to win his old job back -- for the fourth time. Berlusconi, the septuagenarian playboy billionaire nicknamed "Il Cavaliere," has been trailing in polls behind his center-left rival, Per Luigi Bersani. But the controversial media tycoon's rise in the polls in recent weeks, combined with widespread public disillusionment and the quirks of Italy's complex electoral system, means that nothing about the race is a foregone conclusion. Why have the elections been called now? Italian parliamentarians are elected for five-year terms, with the current one due to end in April. However in December, Berlusconi's People of Freedom Party (PdL) withdrew its support from the reformist government led by Mario Monti, saying it was pursuing policies that "were too German-centric." Monti subsequently resigned and the parliament was dissolved.
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Silvio Berlusconi is campaigning to win his old job back for the fourth time
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The eurozone's third largest economy is hurting, with unemployment surpassing 11%
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Pier Luigi Bersani of the center-left Democratic Party is expected to narrowly win
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Italy's political system encourages the forming of alliances
He left at a time of personal and national crisis, as @placeholder grappled with sovereign debt problems and Berlusconi faced criminal charges of tax fraud, for which he was subsequently convicted.