The prime minister is also staking his reputation on a second belief, that Japan needs to restart some of its nuclear reactors to prevent the economy being crippled by energy shortages. (All 54 of them were shut down, at a time of high anti-nuclear feeling, following the Fukushima disaster.) Here, too, Mr Noda is co-operating with the LDP: an independent nuclear regulator is likely to be proposed soon.

ECONOMIST: The prime minister has most foes on his own side

Tepco needs to show it is capable of protecting public safety if it wants to restart its biggest nuclear plant, which has been kept offline like most of Japan's nuclear fleet after the accident.

WSJ: Leaks Rouse Fears at Japanese Nuclear Plant

But Mr Abe, who was elected in December, has indicated he wants to restart the reactors after safety checks to meet pressing power needs.

BBC: Japan marks quake and tsunami anniversary