The government has not kept any records of internal discussions leading up to its reinterpretation of the Constitution last year to lift the long-held ban on collective self-defense, sources at the Cabinet Legislation Bureau said Monday.

The revelation that a government bureau responsible for the legal consistency of policies and bills does not have such public records means it will be difficult to verify in the future how the government came to change the interpretation, which is central to Japan’s security policy, political observers say.

Based on the landmark Cabinet reinterpretation on July 1, 2014, the Cabinet enacted on Sept. 19 the contentious security legislation allowing Japanese troops to fight overseas for the first time since World War II.

The only public documents preserved regarding this Cabinet decision are those related to an advisory panel of security experts for Prime Minister Shinzo Abe and meetings of the ruling parties plus a draft of the Cabinet decision, the sources said.

On June 30, 2014, a day before the Cabinet decision, the National Security Council sent the draft to the legislation bureau, which responded the following day that it has “no comment” on the matter, according to the sources.

The government’s approval of reinterpretation of the supreme law enables Japan to use the right to collective self-defense, or coming to the aid of the United States and other friendly nations under armed attack, even if Japan itself is not attacked.

Previous governments interpreted the Constitution to mean that Japan had the right to collective self-defense but could not exercise it. They had maintained that Japan is allowed to exercise the “minimum” level of self-defense, which does not include collective self-defense. This view was adopted in 1972 in the form of a government statement.

The Mainichi Shimbun newspaper reported Monday that the latest case may run counter to the way the Cabinet Legislation Bureau has handled changes in the government’s interpretation of the Constitution. Previously, the bureau produced detailed records of the legal screenings.

Shinichi Nishikawa, professor of politics at Meiji University, said he is “appalled” by the lack of records, especially because the latest change produced a significant turnaround in Japan’s postwar security posture.

“Administrative bodies must leave records. Without records, how could the public as well as experts examine the process in the future?” he asked.

The bureau is tasked with examining and ensuring that government bills to be submitted to the Diet do not contravene the Constitution. It also gives its opinion on legal issues regarding constitutional interpretation and government policies.

Nishikawa said the Cabinet Legislation Bureau is expected to play the neutral role and at times apply a brake on the administration, adding that it had apparently lost that function.

Two weeks after the Cabinet’s approval, Yusuke Yokobatake, the bureau chief, said in a Diet session that his bureau had been scrutinizing the government’s position since the advisory panel resumed in February 2013 discussions on lifting the ban on exercising the right to collective self-defense.

The bureau looked into past government remarks in the Diet and written answers about the war-renouncing Article 9 of the Constitution, Yokobatake told the Diet on July 15.

Chief Cabinet Secretary Yoshihide Suga said at a news conference Monday, “The bureau has records regarding Cabinet decisions in its possession appropriately under the Public Records and Archives Management Law.”