In Japanese elections, it can take five city dwellers to match the voting power of a single farmer.

The imbalance, a legacy of shrinking populations in rural areas that hasn't been fixed through redrawing the districts, is set to continue as the nation prepares for a general election called by Prime Minister Shinzo Abe for next month. A Supreme Court ruling Wednesday on ballots in the 2013 Upper House election stopped short of invalidating the vote, leaving the discrepancy in legal limbo with little political impetus to end it.

For Abe, 60, who is seeking a mandate for his economic revival program with the nation in recession, the anomaly both helps and potentially hinders. His chances of winning benefit from the ruling Liberal Democratic Party's domination in the countryside, while the out-sized influence of rural voters risks undercutting his push for deregulation and more open trade.