The praise for Turnbull on social media was effusive, with many concluding that Abbott's communications minister had submitted an application for the prime ministership, live on national television. But this was nothing new, as Turnbull's 20 previous Q&A appearances were punctuated with suggestions that he either nominate for the Liberal leadership or set up and lead his own party. For both the ABC and the PM-in-waiting, the association could hardly have been more mutually beneficial, with Turnbull delivering the ratings and Q&A providing the perfect platform to appeal to those in the "sensible centre" with a mix of urbane charm, humour, reason and candour. When, for instance, Turnbull was toppled by Abbott in December 2009 because of his support for Kevin Rudd's market-based mechanism to tackle climate change, the question from Tony Jones was as direct as the answer. "How did you lose the argument in your own party?" Turnbull was asked.

Losing the Liberal leadership was heartbreaking, Turnbull replied, "but what upset me or hurt me the most was the change in policy because I believe we owe it to our children, their children, and the generations ahead of them to take care of the planet …" When, after the dead-heat election of 2010 that saw Julia Gillard form minority government with the support of the Greens and two independents, a questioner lamented the refusal of either Gillard or Abbott to take risks in that campaign, the response from Turnbull was emphatic. "Few have taken more political risks than I have," he shot back. The surprise then, since he toppled Abbott in September last year, is that Turnbull has been so unwilling to take risks. Why, for instance, given his strong belief that the issue of marriage equality was best sorted out by a vote of MPs before the election, did he not stick to his guns and demand government MPs support him? The surprise during the campaign has been that he has been so unwilling to depart from the "jobs and growth" script, so reluctant to take questions (Shorten's people say their man has taken 603 to Turnbull's 362) and so willing to embrace Peter Dutton's fear-mongering rhetoric on asylum seekers.

His finest moments over the past six weeks have tended to be unrelated to the selling of his economic plan, among them expressing his love and admiration for wife Lucy this week when she was honoured for her work strengthening Australia's relationship with Germany. There was also his response to the revelation that an Islamic leader who had condemned homosexuality for attracting "evil outcomes" in 2013 was among the guests at the first Iftar dinner to be hosted by an Australian prime minister: an unqualified repudiation of intolerance and an eloquent assertion of the importance of mutual respect as a bedrock Australian value. On Monday Turnbull returns to the Q&A set for the first time since last February's encounter and it just might be his most daring move in this risk-averse campaign to retain government. The question that will underpin many of the exchanges is no surprise: where is the real Malcolm Turnbull? It's a question that has regularly been entertained by other Q&A panellists, including former Liberal leader John Hewson, since Turnbull's approval ratings began to slide early this year. "There's a fellow running in the seat of Wentworth, my old seat, against Malcolm, who just wants the old Malcolm to come back," Hewson said back in April. "The guy that stood for gay marriage … and climate change and tax reform and so on. And I think that's been a major reason why his popularity has collapsed."

Turnbull, of course, insists he is very much the same man and rankles at the notion that he has been pulled away from the sensible centre to keep the conservatives who stayed loyal to Abbott on side. "All too often," he told my colleague Peter Hartcher last week, when journalists have asked him to respond to the disappointment factor among voters, "they've been unable to provide me particulars, which makes it a bit hard." The Prime Minister can safely assume that there will be no shortage of "particulars" on Monday night, and the Q&A format gives those asking the question ample opportunity to drill down if they are not satisfied with the initial response. Moreover, after constantly interrupting Bill Shorten when the Labor leader made his appearance last Monday, host Tony Jones will be on a mission to give Turnbull the same treatment. The test will be to win over a majority of the studio audience and it is a test Shorten passed early on when he was pressed on Labor's spending commitments on education and the National Disability Insurance Scheme.

When Jones asserted that Labor was placing more weight on its social policies than reaching budget surplus quickly, the reply was emphatic and drew applause: "No. When you talk about social policies, I don't see funding education just as a social policy. It's an economic strategy." Six weeks ago, an appearance on a program that has always provided something of a home-ground advantage would have loomed more as an opportunity than a challenge. Back then, the expectation was that the Coalition would pull ahead of Labor in the course of the campaign, thanks largely to Turnbull's power as a persuader. That hasn't happened. Today's Fairfax Ipsos National Election Poll gives Labor a two-party edge of 51-49, with a fortnight to go. If ever there was a test of Turnbull's ability to charm a room, this might be it.