When it comes to the Democratic Party of Japan's nuclear policy, only one explanation makes sense: Prime Minister Yoshihiko Noda is determined to prove that his party is the bunch of bungling amateurs that the Liberal Democratic Party (LDP) claims it is.

How else to explain the reversals, and then the reversals of the reversals, of the 'no nukes' policy?

On 7 September, a heavyweight DPJ panel endorsed phasing out all nuclear power by 2030. The policy was approved with an extension to the late 2030s by a subcommittee of the Cabinet on 14 September, and endorsed by Noda himself on the same day. Suddenly, five days later, the policy was replaced with complete obfuscation.

This rollercoaster of reversals makes no sense. Substantively, it leaves energy policy in a state of confusion, making it hard for energy-using companies to decide whether to expand - or even stay - in Japan. It also alienates the majority of voters who no longer trust nuclear power.

Some say the final reversal came from huge pressure from Japan's business community, as well as governments in the US, Britain and France. But that suggests Noda did not test the waters before accepting the 'no nukes' stance, hardly the mark of a serious leader. Some say that, because 40 per cent of the DPJ Diet delegation wanted the zero option, Noda only accepted the 'no nukes' goal until he was sure of winning re-election as DPJ president. Then he revealed his true colours.

Prior to 7 September, most observers had expected Noda to choose the middle option among three being discussed for 2030: zero nukes, nuclear power to provide 15 per cent of electricity, or nukes to provide 20-25 per cent. Fifteen per cent was Noda's own personal preference, and it was the preference of another DPJ bigwig, Yoshito Sengoku. Before the Fukushima disaster, nuclear power provided around 30 per cent of electricity, and the Naoto Kan administration had proposed raising it to 50 per cent. In the aftermath of Fukushima, Kan called for nuclear's complete elimination.

So, when the DPJ panel led by policy chief Seiji Maehara and Sengoku came out in favour of the zero option, most observers chalked it up to a desperate election gambit. Now, Noda's reversal has more than offset any electoral gain the DPJ might have made with the 'no nukes' announcement.

The purported objective would clearly not have been realised. The plan is threefold: first, no new nuclear plants will be built; second, no nuclear plants will be extended beyond the 40-year age limit specified by a law put into place after the Fukushima disaster (although the law does allow one 20-year extension if plants are deemed safe enough); third, no shut-down plants will be restarted unless the new Nuclear Regulatory Authority (NRA) can certify their safety.

The reality is, if existing plants are re-started and are all shut down after reaching age 40, nuclear power would still supply 15 per cent of the country's electricity as of 2030. That inertia is one reason politicians found 15 per cent an attractive compromise, as it would allow until the 2050s to reach zero nuclear.

The plan also presumes that renewables will generate 20 per cent of electricity within 10 years, and then 30-35 per cent by 2035, a completely unrealistic target. Noda proposes to achieve it by force-feeding solar, wind, etc. through ¥50 trillion in subsidies, more than all the extra revenue coming from the politically-deadly hike in the consumption tax, to be financed via much higher electricity rates. And the plan requires a much smaller reduction in carbon emissions.

The plan was, in short, a campaign commercial. And so, in the end, Noda muddied the waters.