No hard feelings, eh.

Canada, spurned not long ago at the United Nations, is once again staking out a coveted spot at the foreign policy dais.

Justin Trudeau will address the UN General Assembly on Tuesday, delivering his maiden speech as Canadian prime minister at the high-level diplomatic forum that had an acrimonious relationship with this country's previous government.

The 71st annual session of the largest diplomatic conference in the world presents the first opportunity in a decade for Canada to rebrand itself under a new Liberal leadership — not just as a global power broker, but as the progressive voice of international diplomacy.

Six years have passed since the country's historic loss in its bid for a seat at the UN Security Council; five since Foreign Affairs Minister John Baird struck a combative tone at the Assembly, telling the chamber in New York that Canada refuses to "go along in order to get along" on international affairs.

Baird once dismissed the UN as a "debating club for dictators."

The Conservative government held a skeptical view of the world body's effectiveness given its bureaucracy, with Baird accusing it in 2012 of inaction on the conflict in Syria, saying the UN "must spend less time looking at itself."

Stephen Harper's third and final speech at the main policymaking organ of the United Nations was in 2014, when images of the prime minister addressing a sparsely attended room inspired mockery online.

Trudeau has already announced Canada will seek a Security Council seat for a two-year term beginning in 2021.

"With Trudeau, they're trying to re-engage," says Colin McCullough, author of Creating Canada's Peacekeeping Past. "They're saying Canada is back in the world."

The McMaster University history professor expects a "very, very decided contrast" to the way Harper's government approached its relationship with the UN.

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Trudeau, seen at UN headquarters, has announced Canada will mount a bid for a seat on the Security Council for 2021 and 2022. (Carlo Allegri/Reuters)

One particular example of the Conservatives' disdain for the multilateral gathering sticks out for McCullough.

It happened in 2009, the year of U.S. President Barack Obama's inaugural address at the Assembly. The event was highly anticipated in diplomatic circles. And yet Harper, who was wrapping an American tour the same week, was a conspicuous no-show, choosing instead to return to Ontario to tour a Tim Hortons research and development facility in Oakville, Ont.

"Which just gives you some indication of the way his government felt about Canada and the United Nations," McCullough says.

Harper was also in New York for events in 2012 and 2013, but skipped the Assembly both times.

'Everybody likes Canada'

"Trudeau's government has tried to say that Canada is no longer going to be the country that was strictly concerned with what our national interests would be, and sort of saw no purpose in the UN," McCullough says.

Groundwork has already been laid to make that case, with a $450-million investment for UN peacekeeping operations and a pledge to allot up to 600 troops over the next three years for stability projects.

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Trudeau speaks at the signing ceremony for the Paris Agreement on climate change at UN headquarters in New York in April. Trudeau is expected to address the General Assembly on Tuesday. (Sean Kilpatrick/Canadian Press)

The commitment demonstrates a renewed focus on a liberal internationalist tradition of advancing action on global concerns like climate change, peacekeeping, promoting gender equality and helping Syrian refugees.

Put another way?

"Making the world a better place," McCullough says. "It could be dismissed as overly optimistic, do-gooder talk, but it can help mobilize a large number of Canadians."

[Canada] will be the progressive voice, the conscience that can bring two sides together, and isn't compromised by a close relationship to one adversary or another. - Robert Teigrob, Ryerson University associate professor of history

The exercise in nation rebranding will be important, says PublicisLive founder Richard Attias, who has produced high-level international conferences such as the Davos Forum.

"Everybody likes Canada, and everyone would like to develop a relationship with Canada. So you need to use this … potent asset, because it is an asset to be a loved brand," Attias says, noting that Trudeau "is a brand by himself" with popular appeal.

While Canada is viewed as a "soft power" broker, Attias says, the prime minister will need to reintroduce its potential for being "much more influential in the global conversations" by laying out solution-oriented proposals.

This chance for renewal comes after 2010's stinging denial of a temporary seat on the UN Security Council, widely considered a humiliating episode for Harper in the international arena.

'A slap-down' in 2010

Canada last had a seat on the Security Council in 2000.

The refusal by secret ballot of a two-year, rotational slot — the first such defeat after six elections over 60 years — "was seen as a slap-down" by the global community of 193 voting nations, says Robert Teigrob, an international relations expert who lectures at Ryerson University and co-editor of Canada and the United Nations: Legacies, Limits, Prospects.

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Foreign Affairs Minister John Baird struck an indignant tone during his first speech before the United Nations General Assembly in 2011, saying Canada would not 'go along' in order to 'get along' when it comes to foreign policy. (Sean Kilpatrick/Canadian Press)

He expects Canada to try to restore an image as a non-partisan, honest broker in line with the "sunny ways" doctrine Trudeau has promoted.

"I think it will be the progressive voice, the conscience that can bring two sides together, and isn't compromised by a close relationship to one adversary or another."

With regard to the UN Security Council vote, Teigrob attributes the affront to what was viewed as an isolationist attitude on foreign affairs, notably the Conservative government's support of Israel.

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Trudeau shakes hands with UN Secretary General Ban Ki-moon at the UN headquarters in New York back in March. (Adrian Wyld/Canadian Press)

Though that has always been the policy, he says, "Canada became the biggest champion of Israel among world leaders" to the extent that it drew criticism for being "dismissive" about concerns over Israel's policies and adversaries in the Middle East, and drifting from "the more traditional Canadian policy of evenhandedness."

Kim Richard Nossal, a professor at Queen's University's Centre for International and Defence Policy, is less convinced the rebuff had anything to do with what the Conservative government did, so much as what it didn't do.

The 2010 disappointment was a reflection of the Conservatives' "failure to give representatives a reason to vote for Canada," he says.

Trudeau will need to bring not just a principled presence, but a vision for how to actually help solve global challenges such as terrorism, climate change and keeping Iran free of nuclear weapons.

"Whether he'll try and do this when he visits next week, or whether or not he'll simply lay the groundwork for a later pitch, he'll remind the governments there of Canada's long record of support for the UN, and that the world could do well with having Canada's voice on the Security Council," Nossal says.

With files from CBC's Melissa Kent