A decade after its formation, Nippon Ishin no Kai, the second largest opposition group in parliament, began a new era by electing Lower House member Nobuyuki Baba as its new leader.

After his landslide victory over two rivals on Saturday, Baba said there would be no basic policy changes but promised to make the party a strong challenger to the ruling Liberal Democratic Party.

“I’ll continue the policies of former leader Ichiro Matsui. We’ll work to be the party that stands up to the LDP,” Baba said.

But despite recent gains in July’s Upper House election, Nippon Ishin faces tough questions about whether it can expand its appeal outside its Osaka base. It also needs to distinguish itself among voters who see the center-right party as sharing the ruling LDP's basic positions on economic, diplomatic and defense matters.

Following July’s Upper House poll, Nippon Ishin increased its number of seats to 21, compared to 15 before the election. But in Tokyo and Kyoto districts — key Upper House contests for the party — it failed to beat candidates backed by rival Constitutional Democratic Party of Japan.

Matsui, disappointed with the result, announced he would step down as party leader. He had previously announced he would retire from politics after his term as Osaka mayor ends in April 2023.

Baba, a fourth-term parliamentarian who began his political career as an LDP member in Osaka Prefecture’s Sakai Municipal Assembly, won the three-way race in a landslide, earning 8,527 out of the 11,054 votes cast. Nippon Ishin has about 20,000 members and each member received one vote.

Baba, who was co-leader of the party before the election, was Matsui’s choice as successor and endorsed by Osaka Gov. Hirofumi Yoshimura, whom Baba named as co-leader following his win. Lower House member Fumitake Fujita, who represents an Osaka district, will continue as the party’s secretary-general.

The leadership election and Baba’s margin of victory over challengers Yasushi Adachi, a former industry ministry official, and Mizuho Umemura, a former freelance announcer, was not without controversy. Adachi received 1,158 votes and Umehara earned 1,140, leading to complaints from both that the election had been tilted by the party leadership because the influential Matsui and Yoshimura endorsed Baba over his rivals rather than remain neutral. Baba admitted that the party needed to review how its leaders are chosen.

“The rules for electing representatives should be overhauled, and the issue of how long a leader’s term of office should be needs to be taken into consideration,” Baba said Saturday night.

Nippon Ishin remains a primarily Osaka- and Kansai-centric national party in the more powerful Lower House and has struggled to make gains outside the region. Of the party’s 41 Lower House members, 15 represent Osaka districts, and another 11 come from neighboring Hyogo, Kyoto, and Nara. Six of the party's eight individually contested Upper House district seats are in Osaka or Hyogo, and the remainder are proportional representatives. Baba did not say how the party planned to expand its appeal elsewhere, only that it would enact reforms that would help it grow further.

Nippon Ishin was founded by former Osaka Gov. and Mayor Toru Hashimoto and Matsui in 2012 as a pro-corporate local political party that promised to cut what it deemed as unnecessary bureaucratic expenses, as well as privatize some public services. Its signature goal was to merge the city of Osaka's 24 wards into larger metropolitan regions, a move which would require local and central government approval.

But the party’s efforts to merge the wards was twice blocked in local referendums on the issue.

On national issues, such as constitutional revision, the U.S.-Japan security treaty and defense in the face of a rising China, Nippon Ishin is in basic alignment with the LDP. Hashimoto and Matsui were personally close to former Prime Minister Shinzo Abe, and Matsui remains particularly close to former Prime Minister Yoshihide Suga.

On Friday, Matsui voiced support for the government’s decision to hold a state funeral for Abe on Sept. 27 at a cost of ¥250 million ($1.8 million). He criticized the CDP for saying the plan had no legal basis, saying that the Cabinet had approved it and therefore there was no problem in holding it. Matsui also said he would attend the service.