Do you mind if I raise taxes?

“DO YOU mind if I smoke?” rasps Kaoru Yosano, 72, a survivor of throat cancer. Mr Yosano is no quitter. At an age when, even in Japan, many politicians bow out, on January 14th he performed a flying trapeze act by joining the government of Naoto Kan, whose Democratic Party of Japan (DPJ) he has derided for years.

A year ago, when the DPJ's Yukio Hatoyama was prime minister, Mr Yosano wrote a book called “The DPJ Destroys Japan's Economy”. But that was before Mr Kan took over with the (for Japan) radical promise of launching debate on raising the consumption (ie, sales) tax, which at 5% is the lowest in the rich world. The promise nearly sank Mr Kan, but it endeared him to Mr Yosano. Now the former finance minister (and grandson of two famous pre-war poets) has become Mr Kan's man on tax and pension reform.

It is a gamble. Mr Yosano's appointment offended many in the opposition Liberal Democratic Party (LDP) that gave him a seat in 2009 out of loyalty (ironically, he had lost his Tokyo constituency to the DPJ's Banri Kaieda, whose job in the cabinet he has just taken). Some LDP members may try to blackball Mr Yosano in the Diet (parliament). He has few natural allies in the DPJ, and does not disguise his differences. At heart he believes, perhaps hopes, the LDP can return to power, if only it reforms itself.

Yet Mr Yosano's appointment is bold, too. Even his critics acknowledge that, in taking the job at his age, he is driven more by principle than glory. He believes in urgent tax reform if fading Japan is to shore up pensions, health-care and child-support systems. Mr Kan, whose party lacks a majority in the upper house, needs more such opposition politicians. Mr Yosano may be a good model.

The new minister is still coy about how much the consumption tax should be raised. Like Mr Kan, he appears to think doubling it would be a start. Opponents say that would derail a fragile recovery. But Mr Yosano says that, on the contrary it would give people confidence about the solvency of the pensions system, which would encourage them to spend. He also believes the markets need reassurance about the health of all public finances, which he describes as “far worse than in a few of the worst European countries” (gross debt is twice the size of GDP).

On the timing of a tax rise, opinions in government vary. Koichiro Gemba, Mr Kan's main policy adviser, says a rise in the consumption tax should not be before the next general election, though cross-party talks should start within the next five months, with a tax increase decided by March 2012. Mr Yosano remains non-committal.

In Japan the media and the opposition seize on such differences as evidence of disarray. Yet, with a reshuffled cabinet, the government at last appears to have settled on a message of reform, including of trade and agriculture, that appears refreshingly non-partisan. Among other things, Mr Kan wants a decision by June on whether Japan should begin trade talks, including with America, under the aegis of the Trans-Pacific Partnership, a free-trade block.

For now, squabbling or even gridlock will mark the Diet at least until the spring. The opposition looks determined to try to block Mr Kan's budget, believing the tactic will score points in prefectural and municipal elections in April. But if Mr Kan can ride that out, with public opinion on his side he may yet persuade opponents to support policies that start dealing with the country's troubled finances. Japan's economy, Mr Yosano once wrote, was infected with a grave cancer. The inveterate smoker is now Mr Kan's chief ally in cutting it out.