The average tenure of Japanese prime ministers since the second world war has been just over two years. Before Shinzo Abe, the incumbent, took office in 2012, Japan ran through six prime ministers in as many years (including a prior, yearlong stint by Abe himself).

So the fact that he is nearing four years in the job this time is remarkable in itself. But he seems to be just getting started. His Liberal Democratic Party (LDP) recently decided to extend its leader's maximum term from six years to nine. That paves the way for Abe to remain in office until 2021, which would make him Japan's longest-serving postwar leader.

Admittedly, Abe would need to win both a party-leadership contest and a lower-house election to stay in power that long. But he is an extremely successful campaigner, having led the LDP to victory in two elections for the lower house and two for the upper. Abe's current coalition government holds a majority in both houses of the Diet. Mustering the two-thirds majority in each house that is required to change the constitution seems within his grasp. "He is very powerful," said a lawmaker.

Abe's success does not come from playing it safe: he has pushed for a number of unpopular policies. The government's plan to restart many of Japan's nuclear-power plants, most of which were idled after the Fukushima Daiichi disaster in 2011, is anathema to many Japanese. In early November, the LDP began pushing the Trans-Pacific Partnership, a trade deal about which Japanese feel distinctly lukewarm, through the Diet. Legislation passed last year, which lifted some of the restrictions on the Self-Defence Forces (SDF), as Japan's army is called, was deeply unpopular. Should Abe follow through on his desire to change the constitution to remove the pacifist language still hemming in the SDF, he would doubtless provoke even greater ire.

Even where Abe's goals and those of voters are aligned, such as over the need to revive Japan's economy, his government has disappointed. In a poll published in late October by the Pew Research Center, 68 percent of Japanese said they were unhappy with the state of the economy. Inflation remains far below the government's 2 percent target. Wages have risen only slightly.

Despite this, Abe remains personally popular. A recent poll put his government's approval rating at 60 percent. This is partly because of his adversaries' weakness. He returned to power in 2012 promising national renewal after a disastrous three-year stint in government by the Democratic Party of Japan (DPJ, the main opposition party, now known as the Democratic Party, or DP). The DP's image has still not recovered; the party is trailing the LDP in the polls. It was recently trounced in two by-elections. "He was lucky in his timing," said a DP lawmaker. "We had utterly failed, and he came up with a clear, concrete, alternative message."

Likewise, within the LDP, Abe has few immediate rivals. Electoral reforms in the 1990s greatly reduced the clout of its once all-powerful factions. Abe has empowered Yoshihide Suga, the intimidating chief cabinet secretary, to keep them in line. Colleagues with ambition — such as Fumio Kishida, the foreign minister — have been appointed to grand posts from which they cannot openly criticize him. At the last leadership election, in 2015, he ran unopposed after a would-be rival could not secure the necessary 20 nominations from LDP lawmakers. "As long as he keeps winning elections, we're happy," said Taro Kono, a legislator from the party.

But Abe learned much during his five years in the wilderness, too. Although he does not hide his ambition to change the constitution, he is careful to talk mainly about issues that Japanese people care more about, most notably the economy. "He came back as a product launch, a political slogan: Abenomics," said Jeff Kingston of Temple University.

Abe is a whirlwind of policies, initiatives, trips and summits. "He chases one issue after another, leaving no room for the country or press to get bored," said someone close to him. "Or to notice things left undone," added Koichi Nakano of Sophia University.

All this has had an important effect on the country's psyche, said Natsuo Yamaguchi, the head of Komeito, the LDP's coalition partner. "People are starting to regain the confidence that the past 20 years of political confusion, inward-looking foreign policy and economic stagnation led them to lose, in both Japan and themselves," Yamaguchi said.

Abe has said that voters support him because they are looking for someone with a plan, even if they disagree with bits of it.

In short, Abe is in a uniquely powerful position for a Japanese prime minister. How he intends to use that power remains a bit of a mystery, however.

He has been much bolder, politically, about pushing his ideas on security and international relations than he has about more urgent challenges such as Japan's shrinking population and idling economy. His labor-market and immigration reforms have been timid. He recently abandoned a plan to remove a tax credit that discourages married women from working full-time, which pushes them into insecure part-time work. It would be a shame to accumulate so much authority, only to squander it on less-than-pressing causes.