In today's Upper House by-elections, the DPJ took Fukushima, while the LDP grabbed the seat that the DPJ incumbent had vacated to run (unsuccessfully) for governor. So the split is actually a net gain for the LDP.
But the real story can be seen in Ginowan City, whose citizens have long suffered under the yoke of the US Hutenma airbase taking out a huge chunk of prime real estate. The Ginowan incumbent, supported by the DPJ among otheres, had opposed the Japan-US agreement to transfer to the city of Nago, because he wanted the airbase out of Okinawa altogether. This platform, if admirable, was surely an act of political suicide. The Ginowanese, nevertheless, enthusiastically supported it, if the results mean anything.
Can this incredible act of self-sacrifice and altruism be explained in any other way than by imagining what the Ginowan local economy will look like, if the airbase ever leaves?