Hong Kong(CNN) "We are the future of Hong Kong!"
Edward Leung stands on a crowded overpass connected to a busy metro station, speaking into a white megaphone.
"We will win, we have the mandate!"
Behind him, his round, bespectacled face adorns multiple large banners overlapping those of various political parties, as he and three volunteers hand out leaflets in the sweltering summer heat.
But while he's clearly the main draw -- with several passersby stopping to shake his hand and take surreptitious selfies -- Leung is not a candidate in Sunday's election to the Legislative Council, Hong Kong's parliament.
He was one of several candidates disqualified by electoral officials for promoting Hong Kong's independence from mainland China.
The move, denounced by his supporters as illegal, has made the 25-year-old political philosophy graduate a kingmaker among the city's more radical parties and the figurehead of the Hong Kong independence movement.
It's an idea that was, only months ago, dismissed as impossible but it has gained momentum in the city, livening up what would've been a humdrum vote and angering giant neighbor China.
Banning Leung may end up backfiring on the government and its Beijing masters, says Chinese University professor Ma Ngok.
"He was the only guy who had a realistic chance of winning," he says. "(But now) a lot of people, especially radical voters, will try to send a message to Beijing by casting a vote for one of these groups."
Leung is backing several other independence-leaning candidates still in the race.
"They took one seat from us, we'll win three seats back."
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Earlier this year, election officials issued a warning to candidates reminding them that legislators must vow to uphold the Basic Law, Hong Kong's mini-constitution, which states the city is an "inalienable" part of China.
They also asked candidates to sign an additional declaration, never before used, acknowledging that the constitutional status quo cannot be changed.
Several independence-leaning candidates were disqualified after refusing to sign the new declaration.
Leung however, did sign, and modified the language in his platform to fit the new requirements.
Despite this, he was still barred from running, with an election official saying in a statement there was evidence "he will continue to advocate and support Hong Kong independence," if elected to LegCo.
He is currently seeking judicial review of the decision.
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It's hard to gauge exactly how much support politicians like Leung have.
According to one poll by the Chinese University of Hong Kong, 17% of respondents support independence for the city after 2047.
That is when the current "one country, two systems" doctrine -- which grants Hong Kong limited autonomy and some degree of democracy -- is due to expire.
While 17% amounts to around one million people, or one in six Hong Kongers, only 3% of respondents said they thought independence was likely, and 70% of the over 1,000 respondents interviewed by phone said when asked that they would support the continuation of "one country, two systems" past 2047.
"We localists are fighting for Hong Kong's future, because in the past we did not have a chance to determine our political arrangement after 1997," Leung tells CNN from his office in Kowloon City from where he broadcasts an internet radio show.
"As long as Hong Kong is ruled by China there is no room, no way to realize real democracy and our autonomy. It's very obvious that our liberty, our rights are being deprived."
In some ways localism -- which encompasses a wide-range of views from greater autonomy for Hong Kong to full independence or even return to British rule -- is a successor to 2014's Umbrella Movement.
Those massive pro-democracy protests shut down parts of the city for several weeks but failed to secure any meaningful political reforms. They emphasized reform of the existing system, while localism, by and large, seeks its replacement.
"We realized that after the Umbrella Movement, 'one country, two systems,' is not working," says Leung. "To change Hong Kong society is to submit to (Chinese) authority. The only way to break away from all this control is independence."
Some of the latent Umbrella anger was evident earlier this year when civil unrest broke out in the city's Mong Kok district, as protesters violently resisted police attempts to shut down an unlicensed, but long-running Lunar New Year street food market.
Leung is currently on bail from charges of riot and incitement to riot stemming from those protests. If convicted, he could face up to 10 years in prison.
"People deny the possibility of Hong Kong independence because they say no one is willing to sacrifice themselves for their (political beliefs)," he says.
"I want to prove them wrong. I want to prove that in Hong Kong, young people are willing to fight for our ideas."
Independence doesn't need to be feasible to be worth fighting for, he argues.
"It's also impossible to realize democracy under 'one country, two systems'," Leung says. If all options are impossible, "why don't you ask for a higher one?"
The governments of both Hong Kong and China have been adamant that independence is impossible, and discussion of it absurd and potentially illegal.
Zhang Xiaoming, Beijing's most senior representative in the city, said independence advocacy exceeds "the limit of freedom of speech," while Hong Kong's Department of Justice has stated that it may be contrary to the Basic Law.
"Any proposals or actions advocating 'Hong Kong independence' are in contravention of the constitutional order of Hong Kong and the provisions of the Basic Law," Ronald Chan, Secretary for Constitutional and Mainland Affairs, said in a statement.
Regina Ip, a politician with the pro-Beijing New People's Party, told CNN that "the great majority of Hong Kong people know that Hong Kong independence is neither legal, constitutional nor workable."
Not all voters agree however. In a by-election earlier this year, in which he was not barred from running, Leung came second, winning 15% of the vote, more than enough to win a seat if he were able to run this month.
"If you close all doors, all peaceful means to express their political views, (there will be) more protests, more conflicts and more radical confrontations," Leung says.
"The only thing left is revolution."
That doesn't amount to a call for violence, he's quick to add, pointing to examples such as the Velvet Revolution in 1989, which spelled the end of Stalinist rule in Czechoslovakia.
Leung isn't the only one with color revolutions on the mind. Last month, China's top prosecutor posted an apocalyptic video online warning that the country could become like Syria or Iraq if "separatist" movements in Hong Kong, Tibet and Xinjiang were allowed to succeed.
The video blamed the "dark shadow of the Stars and Stripes," echoing similar accusations of foreign interference in, and encouragement of, the Umbrella Movement.
While Leung does connect his advocacy with independence movements in Tibet and Xinjiang -- "we're all asking for the same thing" -- far from being a foreign agent, he's actually Chinese born.
Leung's parents emigrated to Hong Kong from Wuhan, in Hubei province, when he was just a year old.
"All my values were shaped in Hong Kong," he says. "It's very natural for me to pledge my loyalty to this place."
And Leung says time is on his side, as his generation will one day be the ones in charge.
"Once you advocate for Hong Kong independence, would you go back and think, hey, let's be real, let's embrace China once again?" he asks.
"Once you go radical, it's hard to change back."