With North Korean missiles flying overhead, and an economy that remains sluggish, Japanese Prime Minister Shinzo Abe’s decision to call a snap election on October 20, a full year ahead of schedule, is a high-risk gamble. His hurry to corral the country to the polls with less than a month’s notice stems from a concatenation of factors, including tailwinds to his approval ratings from Pyongyang’s weapons testing and a desire to capitalise on an Opposition in an almost-cartoonish disarray. However, it is from the ashes of this disarray that a genuine threat to Mr. Abe’s ambitions has arisen, with the unlikely melding of a brand new party floated by Tokyo Governor Yuriko Koike with remnants of the erstwhile main Opposition, the Democratic Party (DP).

Ms. Koike, Tokyo’s first woman Governor, is a formidable opponent, who trounced Mr. Abe’s Liberal Democratic Party (LDP) in the Tokyo Metropolitan Assembly elections earlier this year. Many analysts believe that Mr. Abe’s calling of the snap poll was aimed at squeezing Ms. Koike out of the ring by denying her the time she needed to build a national platform and persona.

Collaborative arrangement

However, the Tokyo Governor remained uncowed and calmly announced the launch of a new national party, Kibo no To (Party of Hope) which is already gaining support. Ms. Koike has struck a collaborative deal with Osaka Governor Ichiro Matsui’s Innovation Party but, most significantly, the DP has disbanded itself and encouraged its former members to fight as Party of Hope candidates. For Ms. Koike, the DP’s abundant funding, large pool of lawmakers and nationwide organisation could help in scaling up efforts. For Japan’s usually staid politics, these events are high jinks. However, the outcome of the elections also has global significance, given Japan’s delicate but important role in the North Korea-U.S. stand-off, arguably the most volatile geopolitical hot spot at the moment.

While it is unlikely that Ms. Koike can pull off a straightforward victory against the LDP, a party that has had a virtual stranglehold on national politics since it was founded in 1955, the development to watch out for is whether she is able to inflict enough damage to deprive Mr. Abe of a two-thirds majority in the Lower House. Together with its coalition partner, Komeito, the LDP controlled 323 out of 475 seats in the just-dissolved lower house.

Without this “super-majority”, Mr. Abe won’t be able to pursue his cherished goal of revising Japan’s pacifist Constitution. Mr. Abe considers this vital for a credible response to North Korea’s provocations by giving the military a more-robust constitutional footing.

The challenge for Ms. Koike will be to sufficiently distinguish her Party of Hope’s stand from the LDP’s. The Tokyo Governor is a former member of Mr. Abe’s party and, like him, is a conservative with nationalist leanings. She will need to demonstrate that coming together with the Leftist DP is more than anti-Abe opportunism. So far, her main policy differences from the LDP are on nuclear power, which Ms. Koike wants to abandon, and on a planned rise in the national sales tax, which she wants to freeze. On the crucial question of constitutional revision, Ms. Koike’s stance is equivocal, but going by her past views she is likely to be sympathetic to a shoring-up of Japan’s military.

And yet, there is so much public dissatisfaction with Mr. Abe’s performance in power that his approval ratings fell to under 30% as recently as in July. The most recent Kyodo poll put the LDP’s public support at 24% versus 15% for Ms. Koike’s party. The Koike googly will have Mr. Abe on tenterhooks.