OTTAWA - Nothing less than global economic stewardship and the future of the world's most powerful military alliance are on the line this week as Prime Minister Stephen Harper flies to Europe for two key summits at one of history's crossroads.

While Canada is well positioned to influence both, Harper will be elbowing for space amid a cacophony of often-competing national interests.

"I think we're in a position where we are important players -- people will listen to us -- but not so important that people are worried we have an alternative agenda," Harper said last fall as the Group of 20 countries began deliberations leading to this week's economic summit in London.

It's an evergreen Canadian sentiment that works equally well for both the G20's economic agenda and the following NATO summit with its focus on Afghanistan.

The G20, a relative fledgling among international bodies, which Canada helped found in 1999, meets Wednesday and Thursday amid what its leaked draft communique calls the "greatest challenge to the world economy in modern times, a crisis affecting the lives of ordinary men, women, and children around the world."

Some 35,000 protesters marched in London streets on the weekend, presaging more rambunctious demonstrations expected when the G20 leaders arrive.

The G20 ranges from China, Russia and India to South Africa, Saudi Arabia and Brazil, comprising 90 per cent of world trade, more than 80 per cent of economic output and two thirds of the global population.

For U.S. President Barack Obama, it's his first foray overseas since his inauguration.

Obama will again be front and centre on Friday when NATO leaders convene in Strasbourg, France, to plot the future of the Afghan mission. Afghanistan is a lightning rod for widely divergent priorities among NATO member states as they mark the alliance's 60th anniversary.

Harper will carry the message to both meetings that Canada is on the side of angels.

As the prime minister told a Fox News interviewer in Washington on the weekend, "we're emerging from this (recession) with probably the only truly free-market financial system in the world."

That's a result of Canada's conservative and relatively heavily regulated banking sector, which until recently was considered a stodgy holdover among the world's aggressive financial giants.

Harper pressed home the point Monday in an interview with CNN's Ali Velshi.

"A few years ago Canada was being criticized, we didn't deregulate as much as some others but right now the government is not running all or part of the financial sector as is the case with some many systems.

"Our banks actually for the most part were underleveraged in terms of their maximum allowable ratios when this crisis began," he said.

Now four of the top ten banks in North America are Canadian, as are five of the top 50 in the world, he added.

Canada's banking stability has earned it a significant role at the G20, where Canada co-chaired a working group with India on strengthening international financial regulation.

Their report, released in advance of the summit, proposes 25 non-binding recommendations for increased international transparency and accountability. A number of G20 participants consider a strong commitment to such reforms as the critical outcome of the London meeting.

But it's not the only goal, and that is where things get interesting.

Some countries, including Canada and the United States, want all G20 members to commit to large, immediate stimulus spending plans. Many European countries, including the current Czech president of the European Union, are opposed.

Others want a focus on building up funds at the IMF and World Bank to help developing countries weather the economic storm -- a not entirely altruistic venture. China, with its vast currency reserves, may be prepared to ante up $100 billion US if it can extract much greater influence at the International Monetary Fund and other world bodies.

The Harper government sees the aid question as "secondary."

"No amount of foreign aid and assistance will be sufficient," Harper's spokesman, Kory Teneycke, said at a pre-summit media briefing.

He argued that the best medicine for all -- "including the poorest countries" -- is restoring global economic growth, which requires better financial regulation, dealing with toxic assets and promoting freer trade.

Virtually all G20 members claim to want to curb protectionism, yet domestic politics keep intruding.

A World Bank report recently found that 17 of the G20 countries -- including Canada -- have introduced restrictive trade practices since promising last November to avoid such practices.

The bank included subsidies for automakers among those protectionist measures, arguing they're designed to preserve jobs in less competitive markets at the expense of "more efficient plants abroad in developing countries."

Russia's ambassador to Canada, Georgiy Mamedov, framed protectionist impulses this way on Monday: "It's life. It's like we all have to be law-abiding citizens, but not always we cross the street on the green light, I'm afraid."

So the economic fallout of the London summit won't likely be measured by the volume of solemn declarations made at its conclusion.

When Canada chaired the very first G20 meeting in Berlin in December 1999, Canadian finance minister Paul Martin emerged to declare it a stepping stone to reform.

"If the kind of banking regulation that we are talking about ... and if the kind of transparency in financial statements and openness in dealing that arose out of this meeting had been in place two years ago, there would not have been the bank failures in Thailand and there would not have been an Asian crisis," Martin said at the time.

Exchange the 1990s' Asian economic crisis for the current global financial meltdown and Martin's statement might easily have come from the conclusion of this week's London summit.

And that suggests observers won't know for another decade just how successful Harper and company have been in reordering the global economy.