Agriculture Minister Barnaby Joyce inside his Parliament House office. Credit:Alex Ellinghausen Soon, his dream could be reality. Nationals leader Warren Truss is weighing his future and could resign within weeks. "I've supported Warren publicly and privately and if he steps down I will throw my hat in the ring," Joyce tells Fairfax Media. "The closer you get to the job – and I am close, being the deputy – the more aware you become of the work involved. It's a job I can do but I'm not in a rush." In case anyone doubts his credentials for the job, he lists them: "I've had shadow portfolios, been leader in the Senate, deputy leader of the party, been a successful minister. That's what counts. That's how people judge you when you're running for bigger things."

Agriculture Minister Barnaby Joyce, Prime Minister Malcolm Turnbull and Deputy Prime Minister Warren Truss. Credit:Andrew Meares He's also the only National, he noted, to ever win back an upper and a lower house seat. The message – aimed as much at his colleagues as the public – is clear: I'm experienced. A proven campaigner. Ready to lead. Barnaby Joyce, Deputy Prime Minister? There are apparently many who wake in fright at the prospect. Credit:Stefan Postles According to Keating, there are three types of political leader: straight men, fixers and maddies. Truss, who has led the party since 2007, is the archetypal straight man. While most Australians wouldn't recognise him if they bumped into him in a cafe, he's praised for providing unity and stability.

Joyce, like Keating himself, would be a maddie: high-profile, bold, divisive. Deputy Prime Minister Warren Truss has been seen as a safe pair of hands as Nationals leader. Credit:Alex Ellinghausen There's no policy depth to him. I think he's a goose. Tony Windsor (In 2014, Joyce bought A First-Rate Madness: Uncovering the Links between Leadership and Mental Illness, a book arguing mental instability helped make leaders such as Napoleon, Hitler and Churchill so formidable.) As Nationals leader, he would also be deputy prime minister, ready to lead the country when Malcolm Turnbull travels overseas.

Deputy Prime Minister Barnaby Joyce. If those words fill you with horror you aren't alone. "It would be a bloody disaster for the nation," says Tony Windsor, the former independent MP who is considering running against Joyce in the seat of New England. "The bloke's a fool. Some of the things that come out of his mouth are embarrassing. There's no policy depth to him. I think he's a goose." A cabinet minister says: "When you are deputy PM, you have to be very consistent and measured. That's the concern people have about Barnaby." A regional Liberal MP says: "There is a propensity with Barnaby for a more populist, ill-disciplined side to show its head."

Some have never forgotten his short-lived time as opposition finance spokesman, when he confused his billions and trillions and was criticised by Reserve Bank governor Glenn Stevens for saying Australia could default on its debts. The MP adds: "I wouldn't take it as a fait accompli that Barnaby will win. A large part of the party is not enthused by the idea." In the 21-member Nationals party room, Joyce has a loyal band of followers. But there's another group, known as the Anyone but Barnaby faction, which dreads the idea of him becoming leader. The name most often touted as a possible leadership rival is Michael McCormack, the member for Riverina, an assistant minister who has only been in Parliament for five years. Appointing him the party's leader would be a stunning repudiation of Joyce. NSW Nationals senator John "Wacka" Williams insists it won't happen.

"If Warren did leave I would support Barnaby and I would expect him to stand unopposed," says Williams, one of Joyce's strongest supporters alongside NSW senator Fiona Nash and Queensland senator Matt Canavan. "He's strong, he's tough, he stands up for the things he believes in." Williams says Joyce is the Nationals' best bet of extracting a good deal from their senior Coalition partner. He notes Joyce earned his reputation as a maverick by crossing the Senate floor 28 times – a fact he proudly notes in his official biography. "I want the Nationals to have our fair share of ministers, our fair share of the budget and to stand to our Liberal colleagues on issues such as the misuse of market power," Williams says. The question exercising those on both sides of the Coalition is: how would Joyce work with Turnbull?

When Turnbull last led the party, Joyce, who has expressed scepticism of man-made climate change, led the revolt against his emissions trading scheme. Unlike the Prime Minister, he's a monarchist who opposes same-sex marriage. Last year Joyce claimed Australia's Asian neighbours could see the country as "decadent" if it allows gays and lesbians to marry. In her Quarterly Essay on Turnbull, Annabel Crabb wrote about a Coalition meeting at which Turnbull was discussing Labor's carbon-sink legislation. "Now, what about Eucalyptus globulus?" he asked his colleagues. Joyce responded: "Why don't you just say 'blue gum', Malcolm?" But Coalition insiders caution against overplaying the pair's stylistic and historical differences.

"Because of 2009, a lot of people think Barnaby and Malcolm don't get along – that's not founded in recent reality," says a Liberal frontbencher. "They actually get along quite well and realise they are complementary." Turnbull called Joyce on the night before he challenged Tony Abbott for the prime ministership. He also elevated Joyce to the fifth most senior member of cabinet, ahead of Treasurer Scott Morrison. Asked about his relationship with the new PM, Joyce says he is doing a good job and says they dined together the previous night. "The Nationals have always had respect for the PM. We don't want to be divisive figures fighting our own government but we will push for the best outcomes for regional people. Our job is to go in to bat for them." While no longer the floor-crossing maverick of old, he doesn't want to lose his larrikin edge.

"If you invite me out for a drink, you want me to speak frankly and freely rather than ring up 13 media advisers and get encrypted babble," he says. "One of the great things about Australian politics is our informality and directness and I'd hate to lose that."