Prime Minister Shinzo Abe faced harsh criticism from leaders of the three largest opposition parties during Diet debate Wednesday, including Yorihisa Matsuno, leader of Ishin no To (Japan Innovation Party).

The ruling bloc had hoped Ishin would help the Abe Cabinet enact controversial national security bills, but Matsuno flatly denied that the second-largest opposition party is willing to engage in talks with the ruling bloc over the legislation.

Matsuno’s tough stance may indicate Ishin executives are willing to maintain a fighting posture against Abe. However, some Osaka-based lawmakers are reportedly leaning toward Abe’s Cabinet, leaving the party divided.

“The more deliberations (on the government bills) we have had, (media polls indicated) more people said the Cabinet hasn’t sufficiently explained them,” Matsuno said. “We will not respond to (any call for) talks to amend (the government bills). Instead we will submit our own bills.”

If Ishin were to cooperate with the ruling bloc, it would weaken the impression among the public that the ruling bloc is trying to ram the security bills through the Diet.

Thus whether Ishin will support Abe’s Cabinet has been regarded as a key factor in the fate of the security bills.

Later in the day, a senior government official suggested he believes Matsuno’s tough stance won’t have a big impact on Diet deliberations because if Ishin submits its own security bills, its members will likely attend Diet sessions to deliberate their own legislation.

It would probably make it difficult for the Democratic Party of Japan, the largest opposition party, to keep boycotting Diet sessions in the hope of delaying enactment of the government-sponsored bills.

The two other opposition leaders who attended Wednesday’s session with Abe were DPJ President Katsuya Okada and Kazuo Shii, chairman of the Japanese Communist Party.

Okada harshly criticized the Abe government’s reinterpretation of the war-renouncing Constitution. In July, the Cabinet changed the traditional government interpretation without discussions in the Diet. The Abe administration now maintains that Japan can exercise the right of collective self-defense as defined under the United Nations charter.

Some of the security bills would, based on the new constitutional interpretation, allow the Self-Defense Forces to join operations to defend an allied country.

Okada argued that Abe set a precedent for the government to change the constitutional interpretation without debate in the Diet or in public.

A future prime minister, for example, could change the government interpretation of Article 18 and start saying Japan can introduce a conscription system, Okada charged.

Article 18 reads: “Involuntary servitude, except as punishment for crime, is prohibited.” The government currently interprets “involuntary servitude” term as including conscription into the SDF.

“(Abe) says the Constitution bans conscription because it falls within the category of ‘involuntary servitude’ and I myself agree. But a future prime minister may argue otherwise,” Okada said.