ABIDJAN (Reuters) - The conviction of ex-president Laurent Gbagbo's allies for their role in the violence that followed the 2011 election in Ivory Coast has deepened a rift in his party that risks radicalizing hardliners ahead of polls this year in the world's top cocoa grower, analysts say.
The widening divisions between moderate and hardline factions of Gbagbo's Ivorian Popular Front (FPI) -- Ivory Coast's only major opposition party -- are likely to bolster incumbent President Alassane Ouattara's chances of reelection in the ballot expected in October.
However, the rift could also contribute to renewed instability in Ivory Coast, which, despite its recent history of political turmoil, is seen by investors as one of Africa's rising stars.
"If the hardliners are sidelined, they are just going to say 'There's no place for us on the political landscape, so the only option we have is violence to make ourselves heard,'" said Lori-Anne Theroux-Benoni, director of the Institute for Security Studies' West Africa office.
Verdicts were announced on Tuesday in the trial of 83 Gbagbo allies accused of offences committed during the brief civil war sparked by the ex-president's refusal to accept his defeat to Ouattara in a run-off in late 2010.
Former first lady Simone Gbagbo and two senior military officers were jailed for 20 years for their role in the violence, in which around 3,000 people were killed.
Among others receiving lesser sentences were Pascal Affi N'Guessan and Aboudramane Sangare, the leaders of the two rival factions fighting for control of the FPI and Gbagbo's legacy.
After boycotting legislative and local elections since the crisis, N'Guessan, the party's president, has over the past year attempted to steer the FPI back to the political mainstream.
But he has faced resistance from hardliners led by Sangare, who refuse to participate in political dialogue and elections without Gbagbo -- who is awaiting trial by the International Criminal Court accused of crimes against humanity.
N'Guessan used the courts to successfully fight off an attempt by Sangare's faction late last year to put forward Gbagbo as their candidate in a party leadership challenge. The hardliners responded this month, calling a meeting of party members that suspended N'Guessan and named Sangare interim president.
Tuesday's verdict handed the two men vastly different punishments. The court sentenced Sangare to five years in jail and a suspension of his civil rights while N'Guessan was handed 18 months but credited with time served and released.
Sangare's backers said the verdict was manipulated by Ouattara, who is seeking to ensure peaceful elections to reassure investors but also needs a credible opposition to please donors.
"Pascal Affi N'Guessan seems to have a new friendship with the regime," Alphonse Douati, secretary-general in Sangare's parallel leadership structure, told Reuters. "This was done to block Sangare and have Affi N'Guessan go to the election."
Ouattara has repeatedly proclaimed the independence of the judicial system.
The day after the verdict, government spokesman Bruno Kone reaffirmed that Ouattara's administration considered N'Guessan the FPI's legitimate leader.
On Thursday N'Guessan filed a motion with a court in Abidjan to force the hardliners' to publicly retract their decision to suspend him.
"The problem is that Affi does not receive enough support from the base ... At some point they could be forced to split and form another party," said Rinaldo Depagne, West African project director for the International Crisis Group.
While N'Guessan's participation as a candidate in the presidential polls would mark a step forward for Ivory Coast's languishing reconciliation efforts, some fear the potential reaction of hardliners left out of the process.
"They are no longer a political party. They are kind of a mystical sect, and it's very difficult to try to politically deal with these people, because they are no longer in politics," Depagne said.
Sangare's backers would not be the first Gbagbo supporters to turn their backs on the political process.
In late 2012, unidentified gunmen launched a series of nighttime attacks on army and police installations and infrastructure targets in Abidjan and along the country's borders.
Ouattara's government blamed Gbagbo's supporters, and a U.N. panel of experts found that members of the former regime, who fled at the end of the 2011 civil war, were orchestrating the raids from neighboring Ghana.
The impact of the attacks was minimal and the Ivorian security forces have been largely successful in shutting down the threat to Ouattara's administration.
Many senior Gbagbo government and military officials remain in exile in Ghana and sporadic attacks have continued along the border with Liberia, where thousands of pro-Gbagbo militia live as refugees.
A radicalized wing of the FPI operating outside the political sphere could give a strategy to destabilize the government a domestic foothold.
"They might pose a security risk, not in the short-term perhaps but in the medium to long-term, due to an electoral environment that is unbalanced," Theroux-Benoni said.
Whether political discontent can translate to a serious threat is disputed, however.
Crippled by asset seizures and bank account freezes, the FPI -- moderates and radicals alike -- no longer have access to the financial means they once did. Rumored hidden arms caches have failed to materialize despite countrywide searches. And in a nation weary of war, it is unclear how many could be moved to violence, even among Gbagbo's staunchest supporters.
"Is it dangerous? The answer is, possibly. But are they able to actualize the threat?" one Abidjan-based diplomat said. "Some trouble is possible. But enough to really disrupt? I don't think so."
Additional reporting by Loucoumane Coulibaly; Writing by Joe Bavier; Editing by Giles Elgood