The repercussions continued Friday after independent Upper House lawmaker Taro Yamamoto the previous evening handed an apparently politically inspired letter to Emperor Akihito.

Many lawmakers criticized the rookie politician, a former actor, and some members of the ruling Liberal Democratic Party even called for him to quit the Diet.

Yamamoto, a well-known antinuclear activist, handed his letter to the Emperor when he attended a biannual garden party in Tokyo on Thursday. The letter apparently touched on the radioactive fallout from the crippled Fukushima No. 1 nuclear plant and the situation surrounding the workers dealing with the calamity.

The action by Yamamoto was seen by many as an attempt to use the Emperor for political purposes, an act interpreted as forbidden by the Constitution.

On Friday, several Cabinet ministers criticized Yamamoto, and education minister Hakubun Shimomura even argued that his behavior “is something that deserves resignation as a Diet member.”

According to Kyodo News, Masashi Waki, the LDP’s Upper House affairs chief, told party executives that the LDP should consider proposing a Diet resolution demanding that Yamamoto resign from the Diet.

Land minister Akihiro Ota, ex-head of LDP coalition partner New Komeito, reportedly said Yamamoto’s action was “inappropriate” and that he lacks the proper decorum of a Diet member.

LDP Secretary-General Shigeru Ishiba said the Diet should take strict steps, saying Yamamoto’s deed “cannot be overlooked.”

Jin Matsubara, chairman of the Democratic Party of Japan’s Diet affairs committee, said Yamamoto’s action was unforgivable.

“I share the idea that he should resign as a lawmaker,” Matsubara said.

Since the end of the war, it has been taboo for anyone to include the Emperor in a political agenda, and the monarch himself is not allowed to express any view that could be construed as political.

Article 4 of the Constitution is interpreted as allowing the Emperor to only engage in politically neutral state ceremonies.

On Friday, the Upper House Steering Committee convened an urgent session and asked Yamamoto to explain his actions.

Yamamoto told reporters after the session that he wrote and handed the letter because he wanted the Emperor to learn the true situation concerning the Fukushima No. 1 fallout and the plight of the workers there.

Yamamoto claimed he did not expect his action would be reported by the media or be seen as any kind of political activity.

“I had thought only his Imperial Majesty and people around him would know of the letter, but (this) has been reported by the media,” he said.

“Because you media people play this up, (my behavior) is being used for some political purposes,” Yamamoto said.

Yamamoto said he was not aware that his action was violating any rules, but he will accept any decision by the Diet.

He also argued that if his action is regarded as political activity and he will face punishment, the government should similarly be punished for having a princess from the Imperial family campaign for Tokyo’s bid to host the 2020 Olympics.

Yamamoto, who was elected in July, is known for his radical, if not extreme, anti-nuclear arguments.

He has claimed many children in eastern parts of the country are suffering health problems because of the radioactive substances escaping from the Fukushima plant. Mainstream scientists deny that.

At the Upper House committee meeting, members were split on whether Yamamoto should be punished. The committee will decide Tuesday whether to discipline him, Kyodo reported.

The postwar Constitution was enacted to ban the Shinto-influenced militarism of the 1930s and 1940s, in which the Emperor was used by the military as a untouchable living god to keep the people united during the war.

Article 4 states that “the Emperor shall perform only such acts in matters of state as are provided for in the Constitution, and he shall not have powers related to government.”

According to Chief Cabinet Secretary Yoshihide Suga, the Emperor immediately gave the letter to the grand chamberlain, who was accompanying him.

“By using common sense, people should consider if it’s appropriate to give a letter to the Emperor during such an occasion as a garden party,” Suga said.

It wasn’t immediately known if the Emperor read the letter.