Prime Minister Shinzo Abe's ruling coalition won a landslide victory on Sunday in an election for parliament's upper house, media exit polls showed, despite concerns about his economic policies and a goal to revise the pacifist constitution.
Some of the exit polls also showed Abe's coalition and like-minded parties had won the two-thirds "super majority" needed to try to revise the post-war constitution for the first time, though others only said the threshold was within reach.
Abe's Liberal Democratic Party (LDP) won a simple majority for the first time since 1989, according to the voter surveys, a victory that will bolster the premier's grip over the conservative party that he led back to power in 2012 after three years in opposition.
A push to ease the charter's constraints on the military operating overseas could lead to tension with China, where memories of Japan's past militarism still arouse anger.
Tomomi Inada, the LDP's policy chief, noted that the party had already crafted a draft revised constitution. "Our party is one that calls for reforming the constitution," she told local television shortly after the polls closed.
In Japan, financial market players fear amending the charter will divert Abe's energy away from reviving the stuttering economy.
Some voters who backed Abe's Liberal Democratic Party (LDP) said the economy's health was also their biggest concern.
"Especially since I see economic growth as the priority, I have little hope for the opposition parties," said Yoshihiko Takeda, a 36-year-old IT company employee.
Abe had cast the election as a referendum on his "Abenomics" recipe of hyper-easy monetary policy, spending and reform. With signs the strategy is failing, the government plans to compile a post-election stimulus package that could exceed 10 trillion yen ($99 billion).
But economists worry the government will choose big-ticket infrastructure projects rather than implement tough structural reforms.