The Justin Trudeau of 2019 — the leader who is now seeking re-election — is not the Justin Trudeau of 2015, the young politician who became Canada's 23rd prime minister on a sunny day in November four years ago.

For one thing, the Trudeau of 2019 now knows exactly how much trouble can result when you make an open-ended, but absolute, promise to implement electoral reform.

The promises of 2015 (simple and aspirational) have become an actual record of governing (messy and imperfect). Not everything went according to plan. Some things didn't get done. There is now a list of missteps and controversies for Trudeau's political opponents to recite and dwell upon, from a vacation on the Aga Khan's island to the SNC-Lavalin affair. If Trudeau was a different kind of politician in 2015, he is now some degree closer to being just another politician in 2019.

The prime minister carries all of that into this fall's election. Over the last century and a half, Canadians have shown themselves to be forgiving and patient with their prime ministers — only two first-term majority governments have ever failed to be re-elected — but few of Trudeau's predecessors came to the office with higher expectations.

Trudeau has things to offer in his own defence. The Trudeau on offer over the last four years has arguably hewed closer to the promise of 2015 than he is sometimes given credit for. But the question now is whether he's shown us enough to get another four years.

What 'change' looks like today

In the beginning, there was the promise of "real change." At the most basic level, Justin Trudeau was not Stephen Harper and he promised a clear break from Harper's years in power. "Canadians want their government to do different things, and to do things differently," the new government said in its speech from the throne.

In various ways, big and small, things have been different.

Trudeau marches in Pride parades and is believed to be the first prime minister to ever visit a gay bar. He takes questions from members of the public at open town hall meetings. He identifies himself as a feminist and appointed an equal number of men and women to his cabinet. He has appeared in the pages of Vogue and on the cover of Rolling Stone. These are not things that Stephen Harper did, or would have done.

Prime Minister Justin Trudeau, right, waves to the crowd while waiting to march in the Vancouver Pride Parade with Green Party Leader Elizabeth May, left, and NDP Leader Jagmeet Singh, centre, in Vancouver on Sunday, Aug. 4, 2019. (Darryl Dyck/Canadian Press)

There are myriad policy choices that likely would have gone another way if Harper, or any other Conservative, had been prime minister for the past four years.

Income-splitting for married couples was repealed and the federal system of child benefits was reformed and expanded. The long-form census has been restored. Canadian corporations are now required to publicly report on how many of their directors are women. The national anthem now reads "in all of us command" instead of "in all thy sons command." A majority of the Senate's seats are held by independents. There is, notwithstanding legal challenges launched by three conservative premiers, a national price on carbon emissions, billed as " one of the most ambitious carbon pricing programs in the world ."

When the Harper government left office, Canada was on track to miss its emissions reduction target for 2030 by 300 megatonnes. Taking into account policies announced through 2018, that gap has been reduced by 220 megatonnes.

A man pauses for a moment as he looks over 1,000 crosses during a vigil at Crab Park in Vancouver's east side Tuesday, May 6, 2008. The crosses were placed to represent the lives saved by Insite, the safe injection project that allows drug addicts to shoot up in a safe environment. (Jonathan Hayward/THE CANADIAN PRESS)

In the fall of 2015, there was one supervised drug consumption site operating in Canada — a facility approved by Jean Chrétien's government. In the fall of 2019, there are 44 sites approved to operate in Canada. Some number of Canadians are likely alive today because of that change.

For 2015-2016 — the last fiscal year of the Harper era — the federal government allocated $11.4 billion for programs and services for Indigenous peoples. Under the Liberals, that total allotment is now set to reach $17.1 billion by 2021-2022.

Since November 2015, 87 long-term drinking water advisories have been lifted in Indigenous communities, nearly double the number eliminated in the previous five years.

For those inclined to support the Conservative Party, nearly all deviations from the Harper mean might be unwelcome. A Conservative government presumably would have at least maintained its preference for balancing the budget.

How 'different' is different enough?

It's also within the realm of possibility that Harper — more cautious and fearful of bad press than Trudeau — would have avoided the Aga Khan's private island and stuck to wearing a suit and tie while touring India. It's also hard to imagine Harper's cabinet breaking up over the Shawcross doctrine. (The Conservatives might have found their own trouble, of course — perhaps by proroguing Parliament once or twice more.)

The more significant challenge for Trudeau is in responding to the argument that he hasn't been different enough. Trudeau's government is arguably the most left-leaning and activist federal government since Lester B. Pearson, but progressives and other potential Liberal supporters — voters now pursued with zeal by NDP Leader Jagmeet Singh and the Greens' Elizabeth May — have grounds for complaint.

Electoral reform did not happen — and it didn't happen in spectacular fashion. Canada's international climate target for 2030 is the same as it was under Harper and the current suite of policies doesn't fully account for the necessary reductions.

Trudeau's cabinet approved the Trans Mountain pipeline expansion, just as Harper's cabinet would have (though Trudeau never hid his desire to see a pipeline built). Indigenous reconciliation hasn't been advanced as far as many hoped. Parliament is still being asked to pass budget bills that could stand to be smaller. The access-to-information system is still in dire need of reform.

Nearly every government ends up deviating somewhat from its carefully constructed plans. But when you promise change, you will be judged by that standard.

A party that promised much

According to a count by researchers at Laval University, the Liberal platform of 2015 contained 353 promises — far more than any government in recent memory has brought with it to office. Four years later, those researchers judge that 189 commitments (54 per cent) have been kept in full, while another 136 (39 per cent) have partially fulfilled.

That rate of follow-through is not out of line with the experience of previous governments. The Conservative minority government that existed from 2006 to 2008 managed 60 per cent and eight per cent, respectively. The Conservative majority from 2011 to 2015 (with the benefit of having been in office for five years by then) made good on 77 per cent and seven per cent.

Though his government's record is punctuated by loud misses — electoral reform, returning the budget to balance in 2019 — Trudeau could fairly point to such numbers in his own defence. But Trudeau's politics have always amounted to more than a checklist of items or tasks.

He has campaigned and governed using the language of ideals: change, reconciliation, diversity, feminism and gender equality, transparency and openness, "sunny ways," "we're back," supporting the middle class, fighting climate change. He has been heralded (particularly in the pages of American magazines) as the right sort of leader for this perilous moment.

The price of pursuing the 'vision thing'

Harper tended to downplay his vision of a smaller government and a more conservative country. Instead, he favoured a transactional, incremental politics that worked hard to seem unthreatening. Other than plastering the country with "Economic Action Plan" billboards, Harper tried to avoid attracting any more attention than was absolutely necessary.

Trudeau's approach has been nearly the opposite. He has been prominent and loud. He has embraced "the vision thing." As much as he has promised to do specific things, he has done so using broader appeals to ideas and ideals.

As a consequence, he's given voters ample opportunities to measure reality against his own words.

Consider that stated commitment to gender equality and feminism. Trudeau's government has passed pay equity legislation, uses gender-based analysis to assess the design of its own policies and made a deliberate effort to achieve gender parity in its public appointments.

But his cabinet also has refused to block the sale of light-armoured vehicles to Saudi Arabia, a country where women are subjected to official oppression. And Trudeau's most damaging crisis came when he ran afoul of two strong, independent-minded women: Jody Wilson-Raybould and Jane Philpott.

Prime Minister Justin Trudeau is embraced by Jody Wilson-Raybould, then the minister of justice, after delivering a speech on the recognition and implementation of Indigenous rights in in the House of Commons Feb. 14, 2018. (Justin Tang/Canadian Press)

For nearly every one of Trudeau stated ideals, there have been similar complications and compromises.

The prime minister who enthuses about the power and purpose of diversity has welcomed 40,000 Syrian refugees and increased annual immigration — but his government sent emissaries to the United States to discourage asylum seekers from walking across Canada's southern border. A leader who invokes his children to explain his commitment to combat climate change is still being pressed to explain how he could approve the Trans Mountain expansion — even if neither of the Greens nor the NDP can quite bring themselves to argue that the oilsands should be shut down in the near future.

The politician who condemned the Harper government's attempt to ban the niqab during citizenship ceremonies could be heard again earlier this year when the prime minister spoke about the Christchurch massacre and the threat of white supremacists — but he has been criticized for not doing more to fight Quebec's Bill 21. After promising a more collaborative approach to federalism, Trudeau has found himself fighting openly with the premier of Canada's largest province. The nice young man who promised sunny ways found himself accused of trampling all over the Shawcross doctrine.

Trudeau's recent appearance on Netflix's Patriot Act was a direct confrontation on those terms — a bookend to the generally laudatory coverage Trudeau has received in the United States since 2015.

In their defence, the Liberals might argue that governing is hard and nobody's perfect, that compromises are both necessary and unavoidable, and that ideals — even if they're imperfectly lived — still matter. But any space between words and actions allows room for cynicism to grow.

The political logic of 'not as advertised'

In their pre-election advertising, the Conservatives have, with typical succinctness, hit on this particular narrative. Trudeau, they say, is "not as advertised." It's not an argument that seems designed to persuade potential Conservative supporters: if you voted for change in 2015 and are now disappointed that there hasn't been enough change, you are unlikely to now vote for a Conservative Party that promises a return to the pre-Trudeau state of affairs.

Instead, the Conservative line on Trudeau seems aimed at progressives. It's an attack meant to depress some of the 6.9 million people who voted for a Liberal candidate in 2015 — to either convince them to stay home or nudge them into voting for the New Democrats or Greens (in fact, the United Steelworkers are making almost the exact same argument in telling voters to go with Singh's NDP). If the Conservatives can scatter the Liberal vote, while holding their own traditional level of support, Andrew Scheer can become prime minister.

The presence of Stephen Harper no doubt made it easier to motivate and unite a record turnout for the Liberals in 2015. Four years later, Trudeau's task is to rally non-conservatives around his own government. But he also can't afford to let the election become a simple up-or-down vote on whether Justin Trudeau has fulfilled all of Canadians' hopes and dreams.

Much of one's judgment of Trudeau depends on the point of comparison. So while the Conservatives seek to measure the prime minister against the Trudeau of 2015, the Liberals have decided they are better off contrasting their guy with the only other guy who seems to have a realistic chance of being prime minister at year's end.

The federal Liberals are trying to define Conservative Leader Andrew Scheer in the public's mind on their own terms. (Christopher Katsarov/THE CANADIAN PRESS)

The Liberals have begun to define the alternative. They have put Scheer, who is still relatively unknown to the Canadian public, on the spot over gay rights and abortion — two issues on which Trudeau has taken an enthusiastic stand. They have linked Scheer's politics to the burgeoning record of Doug Ford, the well-known but unpopular premier of Ontario. They have happily invoked the name of Stephen Harper — simultaneously working to fill in their picture of who Scheer is and reminding Liberal voters of why they turned out in 2015.

A more aggressive Liberal campaign

The Liberal campaign in 2015 was not all smiles and sunshine, but 2019 will likely require a feistier effort. The videos on same-sex marriage and abortion that seemed to so discombobulate the Conservative team suggest the Liberal campaign is looking to throw some punches (and is still adept at using social media to advance its cause). Trudeau might need to get his hands dirty. He will at least have to fight to defend his record, particularly in the three televised debates in which he's agreed to participate.

All of that should appeal to Trudeau's competitive streak and his delight at being underestimated. But the Conservatives are also taking aim at the very bedrock of Trudeau's appeal in 2015: the middle class and those working hard to join it.

Four years ago, the Liberals grasped that a significant number of voters were feeling anxious, insecure and squeezed. In response, they offered direct support — in particular, a new child benefit — and public investment. Whatever else the Liberals promised to do, however much more Trudeau came to represent, that appeal to the middle class was foundational. Without it, the whole structure of the Liberal mission would have been in danger of falling apart.

Four years later, the Conservatives have realized the wisdom of the Liberal message and are trying to match it. Scheer is likely to spend most of the campaign touting the different ways a Conservative government would "put more money in your pocket," either through tax breaks or by repealing federal climate policies (though Trudeau's carbon-pricing-and-refund policy is expected to provide a net benefit to most families).

The Liberals can point to their own policies and will no doubt have more things to promise over the next six weeks. But they might not be able to outbid the Conservatives in a dollar-for-dollar contest of tax breaks. To that end, they seem poised to try to broaden the argument, to talk about the future and what it should look like, or about leadership and what it should stand for, or about the country and what it should represent. The Conservatives will have responses for those things, too.

The memory of 2015 will loom over everything and the election of 2019 will, one way or another, be a moment of reckoning for the last four years. But an election is always ultimately about the next four years.