Prime Minister Shinzo Abe’s ruling coalition won a resounding victory in Sunday’s snap election, securing a two-thirds majority in the Lower House that raised his chances of achieving a historic third term and his longtime ambition of revising the pacifist Constitution.

Media tallies showed the Liberal Democratic Party-Komeito bloc won 312 seats in the 465-member Lower House, power that would help it call a referendum on amending the U.S.-drafted charter. This would herald a resurgence in Abe’s drive to amend the supreme code for the first time since it took force 70 years ago.

The LDP endorsed three independents after the poll wrapped up, raising its post-election strength to a total 283, nearly unchanged from the 284 it held before campaigning started, reports said.

Kibo no To (Party of Hope), the upstart headed by Tokyo Gov. Yuriko Koike, struggled at 49 seats.

The Constitutional Democratic Party of Japan, another new party consisting of members who chose not to join Kibo no To, made big headway by bagging 54 seats. This made the CDP the biggest opposition party.

In a televised interview with Tokyo Broadcasting System right after the election, Abe said his ruling coalition alone won’t call for a referendum on constitutional revision, but instead seek cooperation from other parties.

“Kibo no To members maintain a positive or constructive attitude when it comes to revising the Constitution. I’d like to hold dialogue with other parties, including Kibo no To,” Abe said at the party’s headquarters in Tokyo.

Abe said he will reflect on Sunday’s victory with humility and further scrutinize the results so he can decide whether it represents a public mandate.

It was a remarkable moment for Abe, whose grip on power began slipping in July after his LDP was clobbered by a fledgling party headed by Koike in the Tokyo Metropolitan Assembly election. His Cabinet’s popularity had plunged to its lowest point since he returned to power in 2012, damaged by ministerial missteps, gaffes, Abe’s alleged cronyism and a coverup of politically sensitive data in the Defense Ministry.

The solid showing for the ruling bloc could serve as a powerful public mandate for Abe, adding momentum to his widely rumored bid next year to run for a historic third term as LDP president. If re-elected, Abe, who briefly held office from 2006 to 2007, could remain in power until 2021, becoming the nation’s longest-serving prime minister.

Kibo no To’s failure to reach its initially predicted position as Japan’s second-largest party presented the first major setback to the populist governor’s surprising political ascent. It fell far short of its pre-election tally of 57 seats.

Koike conceded defeat after getting early projections, adding that she needed time to analyze the outcome.

“This is a very harsh result,” Koike told reporters in Paris, where she was attending a climate conference. She said her “words and actions” during and before the campaign made voters feel uncomfortable.

Throughout the campaign, Koike coined political catchphrases, including “Yurinomics,” an economic policy that involves taxing firms that stockpile cash, and the “12 zeroes,” a list of reforms that includes eliminating nuclear power, hay fever and rush-hour train hell. But based on the election results, she could end up losing her grip on the party.

Vying against Kibo no To for second place was Yukio Edano’s Constitutional Democratic Party of Japan, which rapidly developed a strong base with its call to “Restore Decent Politics.”

Cameras flashed as Edano stood in front of a makeshift wall covered with the names of the 78 candidates the party fielded.

“I believe our call to change top-down politics resonated with voters,” he said, occasionally smiling as he answered questions from various media outlets.

The CDP opposes Abe’s plan to amend Article 9 of the Constitution to legitimize the Self-Defense Forces in line with the divisive security laws his ruling bloc rammed through the Diet in 2015.

While its second-place finish is unlikely to threaten Abe’s legislative advantage, it would have “symbolic resonance,” vindicating Edano’s emphasis on “uncompromising resistance to Abe’s plans for constitutional revision and past changes to the national security law,” said Tobias Harris, a political analyst at Teneo Intelligence, the political risk arm of consulting firm Teneo.

The opposition slammed Abe’s decision last month to dissolve the Lower House as a self-serving ploy to avoid a grilling in the Diet over his scandals. The questioning had been expected to begin during the extraordinary Diet session called — and immediately dissolved — in September.

Abe, however, said his actions were intended to seek a public mandate for his hard-line attitude toward North Korea and his decision to use the proceeds from the 2019 consumption tax hike to boost education and social security instead of paying down the national debt.

“We can no longer let ourselves be fooled by North Korea. We cannot succumb to its threats. By taking advantage of our strong diplomacy, we have to make sure the North will have no other option but (to) change its policy and return to the negotiating table,” Abe told supporters waving Rising Sun flags at a rally at Akihabara station on Saturday. Abe added he will work in lockstep with U.S. President Donald Trump to continue to “maximize pressure” on the regime.

All eyes are now expected to turn to what happens next regarding Abe’s plan to revise the Constitution now that his ruling coalition, which boasted a pre-election strength of 325 seats in the previous 475-seat Lower House, has successfully maintained the two-thirds majority of 310 all by itself.

The supermajority is crucial to Abe’s goal of revising the supreme law by 2020. In May, he said his aim was to legitimize the existence of the SDF, which some scholars say is unconstitutional under the war-renouncing Article 9. Instead of rewriting the article outright, however, Abe proposed adding a contradictory paragraph to formalize the existence of the SDF, overriding his LDP’s previous goal of a drastic rewrite.

Abe reportedly aims to form a consensus in the party on how to go about revising the charter by year’s end and initiating a referendum next year. To do so, it will also need a two-thirds majority in the Upper House. The ruling coalition lacks a majority but could recruit other pro-revision forces to its cause.

Abe said Sunday night he will reach out to opposition parties supportive of constitutional revision.

Both Kibo no To and Nippon Ishin no Kai (Japan Innovation Party) supported amending the charter during the campaign, but their emphasis was less on Article 9 and more on other articles favoring the people’s right to know, free education and decentralization.

According to Kyodo News projections, voter turnout as of 4 a.m. Monday was 53.61 percent, up 1 point from the previous Lower House election in 2014 but the second-lowest in postwar history. Political apathy among voters and approaching typhoon Lan were likely causes, Kyodo said.

Early voting, however, surged to 21.37 million, for a jump of 62.54 percent

Staff writer Alex Martin contributed to this report