The hottest political issue so far this year has been Prime Minister Shinzo Abe’s historic decision to reinterpret the war-renouncing Constitution to permit the use of collective self-defense, allowing Japan to come to the aid of an ally under armed attack. How has the public reacted to Abe’s military crusade?

Phone-based media polls — effectively the only means by which to rapidly determine voter sentiment — have produced rather perplexing results, stirring debate among academics and the public.

Left-leaning dailies, such as the Asahi Shimbun and the Mainichi Shimbun — which have run editorials opposing Abe’s move — have reported that more than 50 percent of its respondents are against reinterpreting the Constitution to permit collective defense.

But when the right-leaning, Sankei Shimbun and Yomiuri Shimbun — which both supported Abe’s drive — took a poll, they reported much different results: Some 63.7 percent of respondents supported the reinterpretation, Sankei reported after taking a poll on June 28 and 29.

Experts say the contradictory results appear to point to a lack of clear understanding by respondents on the complex issues involved in collective-self defense, rather than bias arising from polling firms.

The results also show there’s a limit when interpreting public opinion on such a complicated issue, said Masao Matsumoto, professor of Saitama University and a noted expert on media poll methodology.

“People don’t know much about this issue (collective self-defense). It is only natural that their answer changes depending on how questions are asked,” he said.

According to Matsumoto, the way questions are phrased is key. The July 4 to 5 Asahi poll and the June 27 to 28 Mainichi poll asked respondents to choose from two options: whether they were for or against Abe’s decision to reinterpret the Constitution to allow Japan to exercise collective self-defense.

By contrast, the June 28 to 29 Sankei poll and the May 9 to 11 Yomiuri poll offered three options, asking whether Japan should be allowed to: 1) exercise the right fully; 2) to the minimum extent necessary; or 3) not at all.

In the Sankei poll, 11.1 percent chose option one, while 52.6 percent chose option two and 33.3 percent option three. Adding up those who chose options one and two, Sankei reported a total of 63.7 percent supported Abe’s plan.

Sankei and Yomiuri apparently prepared option two because Abe’s Cabinet pledged it would use the right only “to the minimum necessary extent.”

But the “minimum necessary” option was not clearly defined in the poll and might have increased the number of people who said they supported reinterpreting the Constitution.

Matsumoto pointed out that Japanese tend to avoid clearly expressing their opinions in public and prefer to choose an intermediate option if multiple choices are available in a media poll. This tendency grows even stronger when respondents are not confident about their answers, experts say.

When Matsumoto and his colleagues at Saitama University carried out an annual poll of 1,000 voters in Saitama Prefecture in June, they asked respondents if they knew what the right of collective self-defense means.

It is a country’s right to use armed force to stop an attack on an ally, even if the first country itself is not under direct attack.

In the survey, as much as 43 percent of respondents answered they “don’t know much about” the right or they “know almost nothing,” Matsumoto said.

“Some people would have known nothing about collective self-defense until they were asked about it in a media poll,” Matsumoto said.

So did the Sankei and Yomiuri intentionally prepare the third option to raise the percentage of people who support the use of collective self-defense, to bolster their political stance? Matsumoto said he can’t tell because he wasn’t involved in the polling.

Generally speaking, however, newspaper companies should be extremely careful in preparing polling questions to avoid giving the appearance of bias, Matsumoto said.

But then, are Asahi and Mainichi polls free of political bias?

In Tuesday’s newspaper, Sankei pointed out that the pollsters hired by Asahi and Mainichi explained in their questions that the Constitution was previously interpreted as banning the use of the right of collective self-defense, before asking respondents whether they were for or against Abe’s proposal.

This information could have subtly steered more respondents to choose the “against” option, because the reinterpretation could have been taken as a taboo, the Sankei argued.

“Media polls may look neutral, but their results are sometimes affected by the intention of each (polling) company,” Sankei wrote.

Matsumoto agreed that the information preceding the question by Asahi and Mainichi might have affected the reactions of respondents, as Sankei pointed out.

Before drawing any conclusion from poll results, people should carefully examine the wording and options presented, the professor said.

“This time, the wording of the question affected the results. This shows voters still don’t have a good grasp” of collective self-defense, he said.