When the BBC spoke to Joyce about the story, the interviewer told him that it was the best read story in the world that day.

As the American TV comedian John Oliver put it, it was "pretty ballsy" because "elected officials very rarely risk openly telling puppies to go f--- themselves". Much less give them a "death countdown", as Oliver described Joyce's 50-hour time limit to expatriate Pistol and Boo or have them put down. "If we start letting movie stars, even though they have been the sexiest man alive twice, to [break quarantine laws] then why don't we break the laws for everyone?" Joyce posed.

Joyce had set out to have an impact. "In that incredibly noisy world, part of the art of politics is getting your message out in a way that people will listen to." He had considered going harder: "If I wanted to say something exceptional I would have pointed out that you can have ten years' jail" for the owner, he tells me. But he knew he was on a winner. "Australians don't like the idea of people who think they occupy a higher realm where they don't have to obey the laws of the land." The radio broadcaster Kyle Sandilands, who occupies such a lofty position in Australian discourse that he is entitled to profane lesser citizens, apparently, decided to interview Joyce to abuse him on air, calling him a "dick", a "wanker" and an "idiot", among other things. But the minister kept his cool. Of the 70,000-odd people who responded to a Channel Nine online poll, four out of five agreed that Depp should face legal action for failing to declare his dogs to quarantine. Depp quietly flew the dogs home. During a visit to Sydney on Friday, strangers approached Joyce on the street to congratulate him on the so-called "war on terriers".

Joyce knew how to catch the media's restless lens, even though he deplores the fourth estate's sense of priorities: "By saying bugger off, I knew that gave it the surety of a run, though I didn't expect it would run around the world. And two dogs are apparently worth more than a heap of people under collapsed buildings" in Nepal.

But why did Joyce decide to go on his little public foray in the first place? "We had just passed the biggest biosecurity legislation in the history of our nation," says Joyce, "and it was about to disappear without a trace." His first motive was to get attention for Australia's tough biosecurity laws, he says. He adds that he wanted to display Australian egalitarianism and "a certain resoluteness". Why? "The US is going to go into the negotiations for the TPP," the Trans-Pacific Partnership, a 12-nation trade deal including the US and Australia. "They're going to say, 'we expect you to put aside your biosecurity issues'. No, no, no. I wanted to make a strong statement. They can read between the lines." Or they can read Joyce's lines spelling it out for them, right there.

So there are a couple of serious underlying purposes in making death threats to a pair of pooches, it turns out. It was an exercise in retail politics and wholesale, too. Tony Abbott once described Joyce as "the best retail politician in Australia". From opposition, Joyce just about single-handedly lit the scare campaign under the idea of an emissions trading scheme that ended up destroying it. Till Joyce got started, it was a bipartisan commitment carried to the 2007 election by John Howard and Kevin Rudd. But Joyce sparked a fire that ultimately burned up Malcolm Turnbull's leadership of the Liberals and burned away the bipartisan consensus on the matter, leaving Australian politics deeply scarred by the politics of climate change.

One of his gifts is the catchy line. He was the father of the famous fright-line that the Gillard government's carbon tax would lead to "hundred-dollar lamb roasts". He uses his gift to do a little roasting of his own, too. He once chided that most truant member of the House, Clive Palmer, for his absenteeism: "Clive's first responsibility as an MP should be to turn up to work — it's a job, not a pedicure." He described Kevin Rudd as a "psycho chook". He sputters original, wacky lines "like a verbal Catherine wheel", in the words of journalist Sophie Morris.

Asked his opinion of the Abbott government's first year, he replied that the first year of any new government was like a "dog fight in a fog; where it's loud, noisy and furious and the targets are shadowy".

Joyce's new international notoriety does raise the question of what he's been doing in his year-and-a-half of near invisibility. What dogfights has he been in concealed by the fog of cabinet confidentiality?

The Queensland farmer and one-time accountant has had some serious wins in the inner counsels of the government. Some have been as satisfying to his National Party constituency as they have been frustrating to big-city corporate elites. Here are three.

First, he and his fellow Nationals pushed the Abbott government hard, and successfully, to block the $3.4 billion takeover of wheat handler Graincorp by the US firm Archer Daniels Midland. The decision was one of only two big vetoes on foreign investment proposals in 30 years. It violated the Liberal Party commitment of open markets and freedom of investment. It came only two months after Tony Abbott's election- night declaration that "Australia is open for business". "Discussions" inside the government "were heated and extensive", says the deputy leader of the Nationals. "In the end the Treasurer agreed with us."

Second, Joyce managed to change the government's position on labelling food with its country of origin. Consumers and farmers have long wanted this; the grocery and food-processing industries have always opposed it, successfully. Or, as Joyce puts it: "You make a lot of money when you put the word 'Australia' on a packet of food, especially if it's from Guadaloupe." Joyce saw his opportunity when the story erupted of hepatitis-tainted Chinese berries making Australians sick. Abbott's initial reaction was to defend the status quo. He said that there would be no labelling of food by country of origin because there was already too much red tape on business. Eventually the Prime Minister conceded the argument after a cabinet debate. Joyce wryly explains his victory: "We got a slightly better poll when we started talking about changing it." Country-of-origin labelling of food is now in train.

Three, Joyce was in the vanguard of Coalition members pushing to put tougher limits on foreign investment in farmland. "People in Sydney always said it was parochialism, so the next thing you know they're having an inquiry into house prices in Sydney," a reference to the work by Kelly O'Dwyer, the parliamentary secretary to the Treasurer, to scrutinise the effect of foreign investment on real estate prices. The upshot? The government announced that a foreign individual has to apply for Foreign Investment Review Board permission to buy land worth over $15 million, and $53 million to buy an agribusiness. A foreign state-owned entity has to apply to buy any land whatsoever.

Joyce also won a conspicuous victory for farmers in the latest federal budget. The Australian Farm Institute's head, Mick Keogh, has said that in the past it's always been better that agriculture is not mentioned in a federal budget "because any mention of agriculture invariably meant a budget cut". The latest budget, however, was "a pleasant change". Smaller-scale farmers will not only have access to the $20,000 instant small business tax deduction on business assets, but also an instant deduction for spending on fences, water and silos, at a cost of $70 million a year to the budget.

The budget announced that this would take effect from mid-2016, a blunder because it would freeze spending for a year as farmers waited for the more generous tax treatment. The government is about to announce that it will bring forward the starting date.

Joyce also persuaded the government to add $498 million in family household allowances for farmers doing it tough by relaxing some of the criteria, as well as an earlier $333 million in extra drought funding for northern Australia, suffering already and now heading into an El Nino-induced dry spell as well.

What's Joyce's power of persuasion? "I will do the job as best I can for as long as I can. But unless you are prepared to give it up, you are compromised by it. If you aren't prepared to walk away from it, people have got you on toast." The threat to resign, even if it's only implied, is a high-stakes way of winning.

But Joyce doesn't seem ready to leave politics. Consider the Ages of Barnaby. From zero to eight years old, childhood, are your best years, he says. The next 10 years are about education. From 18 to 28 are the "best time in life", a time of uni, trying jobs, marrying, he says. The next decade is "for getting serious and digging in". In the years from 38 to 48 "you should be achieving to the best level in your career". From 48 to 58, in the Ages of Barnaby, is "the high spot". How old is Joyce? 48. Terriers everywhere, beware.

Peter Hartcher is the political editor.