Japanese Prime Minister Shigeru Ishiba ’s ruling party, dogged by corruption scandals and plunging support, faces its toughest challenge in more than a decade in Sunday’s parliamentary election.

This could set up a very short-lived time in office for Ishiba, who only took power earlier this month. But even if he may have to take responsibility and step down as head of the party and prime minister, it won’t cause his Liberal Democratic Party to fall from power. That’s because the party, which has had a stranglehold on power since 1955, easily dominates a fractured, weak opposition, which has only ruled twice, and briefly, during that time.

Analysts expect the opposition Constitutional Democratic Party of Japan to significantly gain ground, but not enough to change the government.

“I plan to vote, but the opposition won’t be my choice,” said Kanako Ojima, 48. “I don’t think I want to let the opposition take the helm again. ... I think after all it is the LDP that has a long-term vision.”

The LDP has built its juggernaut of support through a network of bureaucrats, businesses and regional leaders. While opposition parties have made inroads in cities, the LDP controls the countryside, funneling huge government subsidies to rural areas.

Ishiba ordered Sunday’s election on the day he took office, on Oct. 1, aiming to use his image as a reformer to shake off voter anger and shore up power. Analysts say the LDP is likely to lose a few dozen seats and may fail to reach the target Ishiba set for his ruling coalition.

Even in a worst-case scenario, however, the LDP will still be the No. 1 party in the ruling bloc.

Here’s a look at how the LDP has dominated postwar Japanese politics and what virtual single-party rule means for Japan.

The LDP was formed in 1955 by the merger of two major conservative parties: the Liberal Party and the Japan Democratic Party, just as leftwing groups formed the Socialist Party. They led Japan after the war, when conservatives in the U.S.-occupied country were looking to deter the spread of communism.

The party’s rule was only interrupted twice, from 1993-1994 and 2009-2012, both times following bribery scandals. Many credit the LDP with leading Japan’s astonishing recovery after the war, when the nation became one of the world’s biggest economies through the 1980s.

People became used to the LDP dominating the smaller and the main opposition Socialist Party, whose initial ambition to take power faded and was known as the perennial opposition. The LDP and the Socialists were part of a 1994-1998 trilateral ruling coalition until the LDP returned to a one-party reign. The Socialist Party has since renamed itself as the Social Democratic Party.

The LDP’s loss to the short-lived eight-party coalition led by the Japan New Party after two high-profile bribery scandals led to political changes that set up a new electoral system that was supposed to promote two-party competition and eliminate pork barreling.

The current electoral system combines single-seat districts with proportional representation. That means Liberal Democratic candidates only face opposition rivals, rather than competing against fellow party candidates. It has allowed the LDP to concentrate its political resources on one candidate per district.

In traditional LDP strongholds, it has also helped powerful families to take control of electoral districts, funding and connections, with power usually passing to men. Women make up only 10% of the lower house. The LDP has set a goal to increase female candidates to 30% over the next decade.

LDP lawmakers are loosely connected by their support of conservative social values, strong defense policies and a desire to revise the U.S.-drafted war-renouncing constitution. Rather than ideological differences, LDP lawmakers until recently were divided among in-party factions competing for funding and connections that they need to keep winning elections and get favorable party and government posts.

Factional power struggles have led to frequent changes of party leadership and a succession of short-lived prime ministers. Those government changes are meant to regenerate the party, according to Tomoaki Iwai, a Nihon University politics professor.

This is what happened when Ishiba replaced his unpopular predecessor, Fumio Kishida, who resigned in the face of voter anger over a slush fund scandal. Kishida took leadership in the dissolution of most of the LDP factions and revised a political funding law, but voters and critics called the measures too lax.

All but one of six factions no longer have formal structures, but party heavyweights like Kishida and their former faction members were part of a collective effort in backing Ishiba in the party leadership vote.

Support for the LDP is strong among older conservatives, especially in rural areas, but it is weaker in urban areas. That means the LDP relies on an alliance with the Komeito party, which is backed by a Buddhist group called Soka Gakkai that has several million members nationwide. The parties’ partnership began in 1999 during a period of LDP struggles.

The LDP also receives support from industry organizations, fisheries, agricultural cooperatives and religious groups.

The main opposition is the liberal-leaning Constitutional Democratic Party of Japan, but the party has struggled to build momentum despite the LDP scandals. Its newly elected leader, centrist former Prime Minister Yoshihiko Noda, is pushing a conservative shift for the party to attract swing voters, saying that “a change of government is the most effective political reform.”

Media analysts expect his CDPJ to significantly gain ground in Sunday’s elections, but not enough to change the government. That’s because the opposition groups are too fractured. The defunct Democratic Party of Japan, which Noda once led, toppled the LDP in 2009, but lasted only three years, struggling through the 2011 triple disaster of a massive earthquake, tsunami and nuclear meltdown in Fukushima.

The DPJ’s inexperience and shaky handling of the crises disappointed the public and paved the way for the LDP’s big comeback in 2012. Since then the LDP has not faced serious challenges.

Unlike 2009, there is little voter interest in getting rid of the LDP.

Taizo Yoshida, a 45-year-old office worker, said he doesn’t want a change of government and hopes to see Ishiba push through reform. “I don’t think the opposition has the ability to run the government,” he said, though he’d like to see a viable opposition in Japan.

“This party has more of a track record of getting things done,” Rintaro Nishimura, a political analyst at the Asia Group, a strategy and business advisory organization, said of the LDP. With younger people increasingly unhappy about the lack of LDP policies addressing their worries, there may be future changes, but not any time soon. “There is still too much of uncertainty over what the opposition can do.”