ROME (Reuters) - Matteo Renzi looked almost certain to regain the leadership of Italy's ruling Democratic Party (PD), according to early results that gave him an overwhelming lead in a primary election among party supporters on Sunday.
With more than 10 percent of the vote counted, the former prime minister had won about 75 percent of the vote, held in makeshift polling booths around the country. That put him far ahead of Justice Minister Andrea Orlando with 20 percent and Michele Emiliano, the governor of the southern Puglia region, with about five percent.
"This is an extraordinary responsibility. Heartfelt thanks to the women and men who believe in Italy. Forward together," he wrote on Instagram.
While Renzi remains the most popular politician among PD voters, the party and his own appeal look much weaker than it was during his heyday as prime minister, after he failed to convert his ambitious reform agenda into reality.
Renzi's current personal approval rating is about half of the 50 percent he posted three years ago, according to the Ixe polling institute.
Renzi, 42, resigned as prime minister in December after a crushing defeat in a referendum over constitutional reforms aimed at streamlining lawmaking.
He was replaced by his former foreign minister Paolo Gentiloni, but he quickly began planning a comeback.
With a national vote due by May 2018, polls show the ruling PD has slipped behind the anti-establishment 5-Star Movement, which questions the country's euro membership. Renzi's ability to counter the 5-Star surge may be crucial to fending off an existential threat to the euro zone.
However, under Italy's proportional representation voting system, no party currently looks likely to win enough seats in parliament to govern alone.
Renzi, with his confrontational leadership style, has become a divisive figure, and there is no guarantee that he would be named prime minister of a future coalition government even if the PD were to win the most votes at the election.
Polls show 5-Star now has around 30 percent of the vote and a lead of between three and eight points over the PD after a dispute between Renzi's loyalists and left-wing traditionalists caused a party split in February.
"I voted for Renzi because he's got more drive and determination than the others, but I'm not convinced he'll get back into government," said computer engineer Luigi Mancini, a PD supporter in Rimini on the Adriatic coast.
"With the (proportional representation) voting system we've got it seems unlikely that anyone will get a majority," he added.
(Reporting by Gavin Jones and Philip Pullella, editing by Larry King)