Moves are finally afoot for the opposition parties to pursue broad campaign cooperation for the Upper House election this summer to boost their chances against Prime Minister Shinzo Abe's ruling coalition, which has won landslides against the splintered opposition in all national elections since it returned to power in 2012. Long-stalled talks between the largest opposition party, the Democratic Party of Japan, and Ishin no To (Japan Innovation Party) also made rapid progress this week, making a merger likely next month.

Members of the Abe administration and the ruling alliance are quick to denounce the opposition's moves as a marriage of convenience without a cause. To answer such criticism and make their joint campaign more effective and substantial, the opposition parties need to come up with a common policy platform — even one that may be limited in scope — that makes sense for voters.

It was again Japanese Communist Party chief Kazuo Shii who took the initiative. Shii said last week that the JCP was ready to withdraw its candidates in single-member Upper House constituencies where it competes with the DPJ under certain conditions, so as to enhance the chances of an opposition win against Abe's Liberal Democratic Party-Komeito alliance. The outcomes in 32 constituencies, which have one seat each up for grabs in the triennial election that chooses half the Upper House seats, are expected to sway the overall poll results.