Almost two months out from Malcolm Turnbull’s ousting of Tony Abbott and the first great debate of Australia’s new leader is raging. The merits and pitfalls of a rise in the goods and services tax (GST) have swamped the headlines over the past week, and every self-respecting politician and journalist has had his or her say. It’s Turnbull’s first big move — and it’s controversial.

In the United Kingdom, the equivalent debate over a rise in value added tax (VAT) raged just days before the general election in May. Politicians feared it would capture the public imagination — a tax on the nation’s fabled baked beans no less — as Prime Minister David Cameron was forced to hurriedly rule out a rise following opposition pressure and media speculation. The policy threat, once thought to be one of the big issues of the general election, never materialised. The Conservatives romped home and nothing more was spoken of it.

And so it is in Australia. GST has proven the death knell in the past for the likes of Paul Keating and John Hewson, author of the “the longest suicide note in Australian political history”, and nearly John Howard, too. Turnbull, however, has calculated, on the merits of his own strength and the weakness of the opposition, that for him, it won’t be. He’s probably right.

A week is a long time in politics. While the substantive points in a rise in GST may dominate this week’s headlines, it’s not the substance of the debate that will determine the political landscape in the months and years to come. Instead it is the manner in which the policy move was handled on both sides.

And Labor’s proves why the party is in such strife. In truth, the Liberals’ handling of the GST debate has proved bungling and divisive, but Labor’s beleaguered leader, Bill Shorten, failed to capitalise. Instead Shorten, like a schoolboy bereft of his afternoon lollies, moaned of the unfairness of it all. Compare and contrast to Chris Bowen, the shadow treasurer, who homed in immediately on the Coalition’s failure to deliver a concerted economic policy. “Come clean on GST,” urged Bowen, catching out a party that leans so heavily on its competent economics pedigree for, well, not actually having a united economic policy.

It’s not the first time that Bowen has looked more leadership-like than his leader. He is frequently accused of being arrogant and exuding an air of “I know better than you”. Yet Bowen is capable, succinct and a good communicator — and it wasn’t that long ago that Turnbull was dismissed as a future leader for those very attributes.

Similar comparisons can be made to the United Kingdom’s Chancellor of the Exchequer, George Osborne. With an unnerving ability to be photographed looking like Machiavelli’s scheming Prince, Osborne for years never stood a chance as being seen as the next prime minister. Now, as Osborne’s deft hand at political manoeuvring comes to light, the bookies have him as favourite to eventually succeed Cameron, offering odds of 2.50.

There was a time when Shorten was seen as the radical reformer, capitalising on the combative politics of identity to rise to leader of a party licking its wounds after a very public domestic spat. Now, however, the question is not who is Bill Shorten, but what does he believe in? What are his policies? In opposition it’s easy to gloss over these questions for a time, but as prospective prime minister, it’s not.

The Liberals have swooped on the centre ground without being all that central — a damning indictment of Shorten’s failure to capitalise on Abbott’s more extremist far-right tendencies. A similar picture is currently being painted in the UK, but for quite opposite reasons. The Conservatives have a monopoly on the centre ground, but in this scenario, it’s because the opposition are too far the other way. While Shorten appears to stand for nothing, Jeremy Corbyn, leader of UK’s Labour, stands for too much; “communist” is no longer a slur of Corbyn but an everyday description. Corbyn is too extreme; Shorten has nothing of note worth listening to. Moderation in all things, and both the Conservatives and Liberals have made this mantra their own. In the UK, under parliament’s five-year fixed-terms, Labour are widely considered to be consigned to opposition for the next decade. In Australia the feeling is two to three terms.

Where now for Labour and Labor? The plight of the centre-left appears a sombre one. It needn’t be. A quick look across the waters to Canada, a similarly progressive, Commonwealth country and every social democrat’s heart skips a beat. Justin Trudeau, young, liberal and an advocate of “real change” charmed the socks off a nation that had been under Conservative rule for nine years. As recently as 2011, Michael Ignatieff, then leader of the Liberals (equivalent of Labor, not to be confused with their Australian namesake), started his campaign with so much hope only to crash and burn, suffering the worst defeat for the Liberals in history. Social democracy in Canada, too, looked on the wane.

Just a few years later and Trudeau swept to victory, capturing the hearts and minds of not only a nation, but the world. “Why was gender balance in your new cabinet so important to you?” the newly elected Prime Minister was asked. “Because it’s 2015.” A breath of fresh air, an injection of youth, capable in debates, firm economic policies and an ability to say it as it is, Trudeau’s turnaround of the Liberal party proved remarkable. Trudeau’s act is a tough one to follow, but it does at least prove that there is a path to redemption. For UK’s Labour and Australia’s Labor, the first step is acknowledging that there’s a problem. Neither are yet to do so. For Labor, a change in leader would signal that intent. Perhaps this possibility, spoken now only in hushed circles, should be debated more widely. Now there’s a thought.