By Philippa Fogarty
Support for LDP leader Taro Aso has plunged in recent months
Four years ago, Junichiro Koizumi led Japan's ruling party to a landslide election victory.
The Liberal Democratic Party won a two-thirds majority and a seemingly unshakeable mandate.
The opposition was demoralised and Katsuya Okada, leader of the trounced Democratic Party of Japan, stepped down.
Now things have changed. Voters have deserted the ruling party; support for its beleaguered leader, Taro Aso, is less than 20%.
The DPJ looks set to oust the LDP for only the second time in five decades, perhaps even reversing the landslide of 2005.
So what went wrong for the LDP?
Founded in 1955, the Liberal Democratic Party helped transform Japan into an industrial giant.
Working closely with bureaucrats and the business sector, the LDP-led government delivered high growth, ample jobs and a steep rise in living standards.
But cracks emerged when the bubble burst in the early 1990s.
Jobs were no longer for life, a gap emerged between rich and poor and demographic change posed a challenge. Women were having fewer babies and the population was ageing - with serious implications for social security.
Reform was needed but the close bureaucratic and business links that had benefited the LDP also served to constrain it. Efforts foundered in the face of entrenched vested interests.
Part of the problem was that the LDP was slow to get things done, because it was trying to keep a variety of interest groups happy.
"Consensus style meant that strong leadership was not allowed, especially with respect to policy - because you might upset someone," says Dr Steven Reed of Tokyo's Chuo University,
"The LDP could deliver big building projects, but not fix the economy. Demands that were not met at all finally built up to the point where people were no longer interested in dams and roads."
The LDP channelled funds to rural areas, where its support was strongest
Urban voters also felt marginalised as funds flowed to projects benefiting the LDP's rural support base.
"There was a general feeling that the LDP was losing touch and that it wasn't delivering for everybody - that it was working for small cliques and business groups, rather than what was good for Japan as a whole," says Dr Chris Hood, director of Japanese Studies at Cardiff University.
Briefly ousted in 1993, the LDP got back in via a coalition deal with its rival, the Japan Socialist Party.
But over the next decade it did not, Dr Hood says, deal with the fundamental issue of why it had lost power - and calls for change were getting louder.
Then Junichiro Koizumi came along and bought the LDP more time.
He promised economic reform and reached out to urban voters by bringing more women and experts into his government.
He vowed to curb the giant public works projects that brought the LDP rural votes and to privatise the post office - a policy that put him on a collision course with his own party.
Junichiro Koizumi kept the LDP in power, but only by vowing to change it
When his reforms were voted down in parliament, he expelled LDP lawmakers who opposed him and called a snap election.
He portrayed the poll as a fight against traditionalists within his own party who were resisting change - and voters backed him in huge numbers.
"In 2005 it was not the LDP that was popular, it was Koizumi - and what Koizumi said was that he would change Japan by changing the LDP. That's what people voted for," Dr Reed says.
When Mr Koizumi stepped down in 2006, things quickly went downhill.
Japan's system of hereditary politicians had led "to a significant diminishing in the pool of talent" within the LDP, according to Professor Koichi Nakano of Tokyo's Sophia University.
Mr Koizumi's three successors - all sons or grandsons of former prime ministers - lacked his style.
All came under fire for poor cabinet choices and their handling of ministerial scandals. Mr Koizumi's reform agenda was also watered down, leaving some voters feeling betrayed.
Shinzo Abe, who replaced Mr Koizumi, focused on issues such as patriotism and constitutional reform.
But voters did not care. Instead, they were outraged by the loss of pension payment records and increasingly worried about whether the welfare system could cope with the population shift.
They vented their anger in upper house elections in 2007, awarding control to the DPJ. Mr Abe stood down and Yasuo Fukuda took over, but legislative deadlock led to his grey-faced resignation months later.
Then Taro Aso took office - and the economic crisis hit. Giants such as Toyota posted their first annual losses in decades. Businesses empowered by Koizumi-era labour reforms cut contract staff loose. Graduates failed to find jobs and unemployment soared.
Mr Aso did not help matters by making a series of embarrassing gaffes. His cabinet served him poorly too, his finance minister seemed to be drunk at a G8 summit, though he blamed cold remedies for his slurred speech.
A groundswell of public unhappiness coincided with the emergence of the DPJ as a credible alternative - and one with a manifesto promising welfare spending.
"It has reached a point where people want to try something new," Dr Hood said. "They want change and they're fed up with the LDP.
"There's not a huge amount to choose between the two parties. But some of the things the DPJ are talking about are touching a nerve with the electorate."
According to polls, the DPJ is on the brink of a fairly sizeable win.
Whether it can effect the change that voters want, though, is another question.