FOR decades few countries were more evangelical about the charms of nuclear power than Japan, and until the earthquake and tsunami in March last year nuclear plants generated almost 30% of its electricity. Yet by May 5th at the latest, the last of Japan's 54 nuclear reactors will be switched off. Besides those permanently disabled in the Fukushima disaster, the rest have been taken offline for “routine maintenance” and kept that way because there is not enough public confidence in their safety to restart them. In all, that will mean about 50 gigawatts of nuclear capacity has been snuffed out, for the time being. To get a sense of the scale of this, imagine Tokyo (whose peak requirement is around 50GW) without power: no air conditioning, no bullet trains, no neon lights.

Of course, Japan is not grinding to a halt without nuclear energy. Much of the capacity that has been lost or suspended has been replaced by carbon-heavy fossil fuels generating thermal power (and a hefty import bill). But the moment is historic. After Japan, in the mid-1950s, overcame its horror of atomic power from the Hiroshima and Nagasaki bombings, the country became an ardent fan. Until last year, it was planning to generate half its electricity from nuclear sources by 2030. The switch-off marks the death of that passion.

Opinion polls suggest that the public's unwillingness to restart the reactors represents a silent rebuke—this is a country not given to mass demonstrations—to the way the authorities have handled the crisis. Until recently, analysts expected the Japanese to lack the appetite for a second year in a row with the threat of blackouts. Even now, many expect opposition to the reactors to wilt in the heat of summer.

So powerful is the symbolism of having no nuclear plants in operation that Yoshihiko Noda, the prime minister, has tried to get at least two reactors back up and running before May 5th. He has failed, and now his political opponents may try to make capital out of it.

In some respects, Mr Noda and his ruling Democratic Party of Japan (DPJ) can only blame themselves for the mess. Mr Noda has judged that the reactors he wants to restart are safe from an earthquake and tsunami as powerful as the ones that struck on March 11th 2011. Yet the safety tests have been overseen by the Nuclear Industrial and Safety Agency and the Nuclear Safety Commission, two regulatory bodies whose reputations were shredded by last year's catastrophe.

The government's attempt to restart the reactors comes even before a new regulatory body has been established with the transparency, independence and technical ability that its predecessors lacked; before any attempt has been made to clarify the chain of command for handling such accidents, which was a big source of confusion after March 11th; and before government and parliamentary investigations into the Fukushima disaster have been concluded. Their reports are expected to stress the importance of “defence in depth” when regulating the nuclear industry—first, attempt to prevent failures, but always plan for the worst. Instead, the industry remains in the hands of those who argued that the plants were too safe to fail.

To be fair, Mr Noda and his DPJ inherited the problems they are grappling with. During a half-century of rule by the Liberal Democratic Party (LDP), the government joined bureaucrats and big business to promote nuclear power and ease regulations. It is little wonder that the LDP is keeping quiet about the government's predicament. The Yomiuri Shimbun, a pro-nuclear newspaper, has urged the LDP to take a stronger stand in favour of restarting the reactors, to little effect so far.

What both main parties fear is that the nuclear debate could become an electoral issue in what promises to be a stormy summer. The chances are increasing that Mr Noda will have to dissolve the lower house of parliament, either as a condition for winning the LDP's support for raising the consumption tax, on which the prime minister has staked his political capital, or because he may lose the vote on the bill.

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The chances of an election increased further on April 26th, when Ichiro Ozawa, a staunch opponent of the tax increase who was recently suspended from Mr Noda's party, was acquitted of allegations that he had broken a political funding law. The return to the DPJ of this heavyweight will increase his nuisance value.

Yet an election may play into the hands not of the LDP, the official opposition, but rather of a nationalist firebrand, Toru Hashimoto, the mayor of Osaka. That big city gets its power from Kansai Electric, operator of the plant at Oi in Fukui prefecture that Mr Noda wants to restart. Nevertheless, Mr Hashimoto has loudly protested against the plan. He has called for stronger safety measures and demanded that cities like Osaka, within a 100-km (62-mile) radius of Oi, should have a say on whether they are adequate.

The government is trying to shrug off Mr Hashimoto. But analysts say that his Osaka-based party, though parochial now, could use the anti-nuclear issue as part of a platform to vault to national prominence in a general election. If the election became a vote on Fukushima, neither the DPJ nor the LDP would relish the result.