Sunday's runoff pitted veteran Pier Luigi Bersani, 61, against the 37-year-old mayor of Florence, Matteo Renzi, who campaigned on an Obama-style "Let's change Italy now" mantra that has attracted many disgruntled Italians back to politics.
Nearly all polls projected Bersani, the leader of the main center-left Democratic Party, as winning Sunday's primary. He won the first round of balloting Nov. 25 with 44.9 percent of the vote to Renzi's 35.5 percent.
With Silvio Berlusconi's center-right People of Freedom party lagging in the polls and in chaos over whether the three-time premier will run again, analysts were already discussing the possibility that Bersani could soon become Italy's next premier.
The 2013 general election — expected in March or April — will decide if Italy continues on the same path to financial health charted by Premier Mario Monti, appointed last year to save Italy from a Greek-style debt crisis. The former European commissioner was named to head a technical government after international markets lost confidence in then-premier Berlusconi's ability to reign in Italy's public debt and push through structural reforms.
Even if Renzi loses the primary, he will have won a victory of sorts in having changed the Italian left. Renzi's perceived conservative leanings, while alienating the left's hard-core communists, attracted Italians young and old who have grown disenchanted with Italy's political class.
"Even if he loses, as I think he will, he had an important renovation function within the party," Rome resident Pietro Marucci said Sunday as he voted for Renzi.
Renzi's style — moving around Italy in a motor home to meet crowds, addressing supporters in just a shirt and tie, no jacket — attracted quite a following and drew inevitable comparisons to Barack Obama.
But some analysts said he was simply not yet ready for the job of running Italy, and that his relaxed, fresh approach to politics isn't what Italy needs as it navigates through a grinding recession and near-record high unemployment and tries to tackle its enormous public debt of €2 trillion ($2.5 trillion).
"Italy certainly badly needs new faces, fresh faces," commentator Massimo Franco said. "But I think that between Renzi and Bersani, the big problem is also experience."
Renzi shot back at that charge during a debate this week, asking Bersani, who has served previously as national transport and industry minister, what he had accomplished in his 2,547 days in government.
Renzi also complained bitterly this week about primary rules that limited voters and his campaign reported alleged voting irregularities on Sunday.
Primary organizers said they were investigating a handful of individual cases but that on the whole voting was proceeding regularly.
Berlusconi had largely stayed out of the public spotlight for the past year — until recent weeks, when he announced he was thinking about running again, then changed his mind, then threatened to bring down Monti's government, and then went silent about his political plans.
His waffling has thrown his People of Freedom party into disarray, disrupting its own plans for a primary.
A poll published Friday gave the Democratic Party 30 percent of the vote if the election were held now, compared with 19.5 percent for the upstart populist movement of comic Beppe Grillo. Berlusconi's party was in third with 14.3 percent. The poll, by the SWG firm for state-run RAI 3, surveyed 5,000 voting-age adults by telephone between Nov. 26 and 28. It had a margin of error of plus or minus 1.4 percentage points.
It's been quite a turnabout both for Berlusconi's once-dominant movement and the Democratic Party, which had been in shambles for years, unable to capitalize on Berlusconi's professional and personal failings.
Another unknown is Monti's political future. He has ruled out running for office but has said he would be willing to stay on in some capacity if he could be of service. Some commentators have floated the idea of Monti taking over the largely ceremonial role as Italian president, while others say his talents would put to better use as treasury minister.
Maria Grazia Murru contributed from Rome.