For the past year, the top question on the minds of many South Koreans was whether Ahn Cheol-soo would seek the nation's top job. On Tuesday, the doctor, turned software entrepreneur, transformed himself once again into a politician and announced his bid for the presidency.

"I will make the hopes of the citizens become a reality," Ahn told a crowd of supporters in Seoul. "Old politics should be overhauled. I will run for president."

A bid for change

His decision to run after months of speculation came as a breath of fresh air to many young and progressive South Korean voters who have grown weary of various corruption scandals and broken promises of both the ruling and main opposition parties.

Recent opinion polls put 50-year-old Ahn just behind frontrunner Park Geun-hye, the daughter of a former military dictator, whose victory in the December election was all but certain until today. Some political observers say she should be worried now that Ahn has joined the race.

"Things have become a lot more difficult for Ms. Park," says Jasper Kim, director of the Asia Pacific Global Research Group in Seoul. "Anything can happen. He has muddied up the waters."

Kim compares Ahn to Ross Perot, the third party candidate in the 1992 US presidential election, who shook up the mainstream parties though in the end, he fell short of winning a majority. Ahn's greatest strength, according to Kim, is his novelty. But many questions remain about where he stands on important domestic and international issues.

"He is a known unknown quantity. He paints in very broad brush-strokes. He speaks in almost parable-like fashion. It captures the current angst that exists in Korean society," he says.

Voter frustration
 

That frustration, Kim adds, is the result of perceived economic inequality, corruption and political favouritism to South Korea's chaebols - conglomerates such as Samsung or Hyundai. Where he stands on issues like trade with the United States or policy toward North Korea will not be a factor in this election.

But Ahn's decision to announce his candidacy this late in the game could work against him. Some young voters, who were fans of his motivational speeches and successful business career, have begun to doubt that he is a serious contender due to his vagueness on certain issues.

"He has been ambiguous on his positions. It seems like he just can't make up his mind," Choi says. "But at least he doesn't come from the privileged class, like Park Geun-hye," says 24-year old Choi Ji-eun, a master's degree candidate in history at Seoul's Sangmyung University.

Choi says that since she's lost hope in Ahn, she will now throw her support behind Moon Jae-in.

Jasper Kim says that as the election nears, Ahn will no longer be able to dance around the issues and must make his stance clear, which might push even more supporters away.

"The more that people know about him, the more he will be scrutinized," says Kim. "His popularity may have already peaked."