The support for Hong Kong's pro-democracy camp has never been so divided.
And this divided support - with some traditional voters of the pan-democrats expected to defect to young candidates from the more radical new political parties - could mean the pan-democratic camp may fail to garner one-third of the seats in the 70-seat Legislative Council (Legco) in Sunday's polls.
If they fail to do so, they will lose the power to overturn decisions of the government in Legco - the power of veto.
"It will be a disaster for Hong Kong people," said political analyst Johnny Lau. "If they lose (their veto power), I think the Hong Kong government or pro-establishment camp will try to change the regulations in Legco in the future."
Mr Alan Leong, leader of the Civic Party, one of the pan-democratic parties, foresees the city's government trying to re-introduce a political reform package which the pan-democrats had vetoed last year.
Uncertain future for Leung if pro-establishment camp fares badly, say analysts
Unlike previous Legislative Council (Legco) elections, this year's poll results will be closely tied to next year's election for the Chief Executive, some analysts have said.
Whether current Chief Executive Leung Chun Ying will get a chance to stand for re-election next March will depend on how many seats the pro-establishment camp wins on Sunday, they say.
The deeply unpopular Mr Leung, the city's highest-ranking official, has been the target of the opposition camp in their election campaign in the past one month.
In their effort to win more votes, many opposition candidates brought up policies under Mr Leung's administration that are unpopular with Hong Kongers, such as the political screening of Legco election candidates. They vowed to stop him from running for a second term.
If the poll results show that the pro-establishment camp has lost seats because of Mr Leung, then Beijing may consider replacing him as a candidate for next year's Chief Executive election, said political scientist James Sung.
What has puzzled many in Hong Kong, meanwhile, is a commentary earlier this week in Hong Kong's oldest Chinese-language newspaper, Sing Pao. It alleged that Mr Leung has encouraged independence talk among Hong Kongers so as to consolidate the authority of his governance.
Analysts were surprised to read the full-page article on the front page of a pro-Beijing newspaper that appears critical of Mr Leung.
While he did not comment on the motivation for the article, political analyst Johnny Lau said people will be watching out for further developments to the article.
He, however, does not think the Legco poll results will affect the Chief Executive election. The influence "will be very limited" as the two elections are different in nature, he said.
Beijing will not consider the results of the Legco elections because it just wants the future Chief Executive to act as a figurehead for China, said Mr Lau.
The reform package would have introduced universal suffrage for the election of the city's Chief Executive, but under restrictive conditions opposed by the pan-democrats and pro-democracy Hong Kongers.
In the thousands, Hong Kongers, many of them students, camped out in the streets in the Occupy Central movement of 2014 to demand freer elections.
While the protesters failed in their bid, the movement spawned several new parties set up by young people who want greater autonomy and to preserve the city's culture and identity.
Some of them want the city to break away entirely from mainland China, to which the city returned in 1997 under the One Country, Two Systems framework, in which the city is to enjoy a high degree of autonomy but which Hong Kongers feel is being eroded.
These new parties are now challenging the traditional pan-democrats - themselves pro-democracy youth activists of the 1970s who went on to take part in the electoral politics of the 1980s introduced by the British colonial government.
In the last Legco polls in 2012, pan-democrats won 27 seats. To maintain veto power, the pan-democratic camp needs to win more than 23 seats in Sunday's polls.
The chairman of The Democratic Party, Ms Emily Lau, said she remains "cautiously optimistic" that voters would continue to support the pan-democratic candidates.
"It (veto power) is important because we have to be able to restrain the administration. Or there will be a tragedy," she said.
She added that people may be forced to protest in the streets if there is no way to restrain the government in Legco.
Asked if pan-democrats should be cooperating with the newcomers in order to veto any constitutional reform, Ms Lau replied: "I am always in favour of working with people, even with the pro-establishment people. But they had refused to work with us."
Pro-independence activist Edward Leung, who is running the campaign for localist party Youngspiration, thinks the only way out for the opposition camp is to cooperate with one another to veto any constitutional reform.
But the radical activist - who has been barred from running in Sunday's polls because of his pro-independence stance - told The Straits Times he does not think it would be possible for localist candidates to work with the pan-democratic parties because the pan-democrats "could not even cooperate among themselves".