Finding venues for opposition meetings has never been an easy task under the iron-fisted rule of President Alyaksandr Lukashenka.
This time, however, Minsk authorities have given the green light to the congress -- possibly as a result of U.S. and EU threats to slap further sanctions on Belarus if it fails to loosen its grip on the opposition.
The gathering is a rare opportunity for the opposition coalition to make strides in challenging Lukashenka's regime, at a time when the government's energy-price row with its traditional ally, Russia, has forced it to make conciliatory moves toward the West.
"There is no obvious opposition leader who is recognized by all," Karbalevich said.
It's a time when the opposition could be coming out strong. The congress, however, is likely to be marred by bitter divisions over the coalition's leadership.
Valery Karbalevich, an analyst with the Strategy political think tank in Minsk, said the opposition is suffering from a lack of unified leadership.
"The reality is that there is no obvious [opposition] leader who is recognized by all," Karbalevich said. "Either this leader is artificially elected, or a system of rotation is created to allow for several united coleaders. Most opposition leaders have a preference for the coleadership system."
A Contested Leader
Alyaksandr Milinkevich was elected as the unified opposition's presidential candidate in October 2005. But he was defeated in the March 2006 elections -- where vote-tampering was believed to have made Lukashenka, the incumbent, virtually impossible to beat.
Milinkevich became widely known in the West as the face of the Belarusian opposition. But since his defeat, a number of his fellow opposition leaders have been contesting Milinkevich's chairmanship.
The upcoming congress is due to vote on a proposal to divide the leadership between five regional cochairmen, or, alternatively, make the chairmanship a rotating post open to all opposition party leaders.
Milinkevich this week announced that he will not run for cochairman, calling this system "weak and inefficient."
Despite internal strife, political analyst Karbalevich says the Belarusian opposition deserves to be credited for one major achievement.
"No one else in the world has nationalists, liberals, social democrats, and communists united into one coalition," he said. "This has happened in Belarus, and that's precisely the problem -- the problem of finding an ideological, political platform and a mechanism that enables decision-taking and the ability to function."
Oppositions Divided Throughout The CIS
Belarus is not unique in terms of infighting within opposition ranks.
In Russia, opposition forces are largely fighting individual battles against the political domination of the pro-Kremlin ruling party, Unified Russia.
A number of opposition and human rights groups united in July 2006 into a loose coalition called Other Russia. The group is stepping up its activities ahead of parliamentary elections in December 2007 and presidential elections in March 2008.
But the participation of firebrand groups such as the outlawed National Bolshevik Party has prompted Russia's two leading opposition parties -- Yabloko and the Union of Rightist Forces (SPS) -- to stay clear of the coalition's trademark March of Dissent rallies.
Masha Lipman, a Russian journalist and political commentator, says Kremlin control over political life is largely responsible for the country's fractured opposition.
"In a situation where the Kremlin has 100 percent control over the country's political life, it's easy to understand why there's no unity among dissenting forces," Lipman said. "The possibility of forming a coalition is to a large extent determined by the belief that being together improves one's chances of coming to power. But when these chances are nil, there is no incentive for unification."
Central Asian states also provide glaring examples of infighting and disarray within antigovernment forces.
In Kazakhstan, for instance, the Ak Zhol (Bright Path) opposition party won a seat in the September 2004 parliamentary elections, making Alikhan Baimenov the only opposition deputy in parliament.
Five months later, Baimenov called an emergency meeting and obtained a vote of no confidence against several cochairmen of his own party. The move appeared to reflect his hostility to plans by some Ak Zhol party leaders to form an opposition coalition aimed at unseating President Nursultan Nazarbaev in the December 2005 elections.
It provoked a furious response from Altynbek Sarsenbaev, one of the party's ousted party cochairmen. "Who organized this?" Sarsenbaev asked. "Because this doesn't deserve any attention. If [Baimenov] considers himself a democrat, he should not stab people in the back who are struggling with the authorities. This is why you need to ask him, who helped organize this plenum? Why is he bringing the party to the brink of ruin at a time when Kazakhstan's democratic forces are under growing threat?"
Sarsenbaev and other Ak Zhol leaders subsequently split from the party to form a dissident faction named Naghyz Ak Zhol (True Bright Path).
In the meantime -- in Kazakhstan, Russia, Belarus, and elsewhere -- the ruling regimes show no sign of losing strength.
(RFE/RL correspondent Bruce Pannier contributed to this report.)