IN 2009 Mrs Hattori, a housewife voting in Iwate prefecture in the north-east of Japan’s main island, says she helped impose a stinging defeat on the Liberal Democratic Party (LDP) at the hands of its rival, the Democratic Party of Japan (DPJ): after decades in power, she thought, an arrogant LDP needed humbling. But on July 21st Mrs Hattori says she backed the LDP in a crucial election for the upper house of the Diet. She was taken by the idea of “Abenomics”, a popular plan for Japan’s economic revival designed by Shinzo Abe, the prime minister. A measure of humility certainly lay in Mr Abe’s pledge, immediately after winning a handy victory, that he had listened to voters and would tackle the economy ahead of anything else that his government might cherish.

Every three years half of the upper house’s 242 seats come up for grabs. Mr Abe’s ruling coalition, of the LDP and New Komeito, a Buddhist-supported party, needed 63 seats to win back control of the powerful house. The LDP’s loss of its majority in 2007, to the DPJ and other parties, precipitated the end of Mr Abe’s terrible first term as prime minister. Legislative gridlock ensued, leading to the LDP’s complete fall from power two years later.

On July 21st, with cries of “Banzai!” ringing out in campaign headquarters, the coalition won 76 seats to add to the 59 it took in 2010. It constitutes a solid majority for the coalition, though not for the LDP, with 115 seats, alone. The DPJ, on the other hand, won just 17 seats, for a total of 59, and lost its footing even in its urban strongholds of Tokyo and Osaka. One of its most popular figures, Goshi Hosono, a member of the Diet’s lower house, said he would step down as secretary-general. The future of the party leader, Banri Kaieda, is in doubt. Much soul-searching will ensue. If the party does not radically reshape itself, it may soon struggle not only politically but financially, too.

Fortified by his triumph, Mr Abe should now be free to press on with a robust version of Abenomics and its three “arrows”, of radical monetary easing by the Bank of Japan, extra fiscal stimulus of ¥10.3 trillion (about $100 billion) and supply-side reforms and deregulation. Before the election, LDP members warned that anything too radical could turn away voters. In June Mr Abe released only mild proposals for structural reform, disappointing the financial markets. Now he has no excuse to shrink from his task. A “second season” of the third arrow is expected in the autumn.

Those in favour of reform have a long list of demands, such as easing rules against sackings. Japanese agriculture could be made more competitive by lifting government limits on rice production, or by allowing companies to buy, not just rent, farmland from ageing and often inefficient small farmers. As for health care, another crucial area, in June the government proposed some easing of the tight regulations on medical treatment, which prevent patients from combining state-covered and private care. But this could go much further.

A problem is that a big chunk of Sunday’s seats were allocated, through proportional representation, to opponents of reform from within the coalition. They include the vice-chairman of Japan’s medical association and vocal critics of Japan’s move this week to join talks on the Trans-Pacific Partnership (TPP), a regional free-trade grouping. In the lower house anti-reform members of the LDP and New Komeito, confident of their seats, may now be emboldened to resist Abenomics more forcefully. Jakob Edberg of GR Japan, a lobbying firm, thinks that when the third arrow is properly loosed, it may consist of narrow, technical changes to regulations rather than a broader ideological push towards a more market-oriented economy.

A different sort of change may be on the horizon, however. The combination of the LDP, New Komeito and two small right-wing parties, the Japan Restoration Party and Your Party, together account for 162 seats, or a hypothetical two-thirds majority in the upper house. The coalition already holds a two-thirds majority in the lower house; these two majorities, if wielded, together with a majority of votes in a national referendum, are sufficient to amend the constitution.

Rewriting Japan’s liberal constitution, drawn up by America during its occupation in 1946, is Mr Abe’s dearest wish. Admittedly, he will need to persuade New Komeito, traditionally averse to constitutional change; but then it has also been averse to free trade and other reforms, and that has not always seemed to count for much. In other words, if New Komeito is willing, constitutional revision could become a possibility for the first time since the war. Momentum for change continues to build, says the Asahi Shimbun, a left-leaning newspaper. In a poll, it found three-quarters of the upper house of post-election members in favour of revision.

Mr Abe wants to rewrite irksome elements of the constitution, such as the pledge never to maintain a standing army, navy or air force (Japan already has powerful “self-defence forces”). He also wants to reintroduce pre-war anachronisms, such as reverence for the emperor and for the traditional family unit.

Mr Abe has pledged to keep revision down the agenda for now. Instead he says he will concentrate on strengthening Japan’s national-security apparatus by setting up a national-security council. Mr Abe will also press ahead with a less controversial reinterpretation of the constitution to allow Japan to come to the defence of its allies if they are attacked. Deciding how to alter the constitution will require a deep public debate, he said this week.

Even if he leaves constitutional revision aside, Mr Abe could have great bearing on Japan’s most important relationships in the region. During the campaign he struck a hawkish stance against China’s ongoing challenges to Japan’s control of the Senkaku islands in the East China Sea. (China, which calls them the Diaoyu, claims the tiny isles.) Even so, say the Japanese, both sides are working hard behind the scenes to try to ease tensions. Efforts are being made to set up a meeting between Mr Abe and Xi Jinping, China’s president. Diplomats are also working to prepare the ground for a meeting with Park Geun-hye, South Korea’s new president.

The prospect of such breakthroughs would vanish, however, if Mr Abe chooses to visit the controversial Yasukuni shrine in Tokyo, where high-ranking war criminals are honoured among Japan’s war dead. Mr Abe holds kookily favourable views about Japan’s war record. The days around August 15th, the anniversary of Japan’s defeat in the second world war, when visits to Yasukuni surge, are particularly sensitive. It is a dangerous time, too, around the Senkakus, where ultranationalists on both sides have attempted to posture in past years. Mr Abe will not say whether he will join dozens of other lawmakers who are sure to be at Yasukuni. Certainly, he knows that it is not a visit that Japan’s economy-obsessed voters have asked him to make.