The prime minister joined the leaders of the U.S., Britain, France, Germany, Italy and Japan in their united front Monday, isolating Russia as punishment for last week's annexation of Ukraine's Crimean peninsula.
Russia appeared to brush off the spectre of being kicked out of the G8 amid political, diplomatic and military developments that have Europeans fearing a dangerous escalation of the conflict.
“If our western partners believe the format has exhausted itself, we don’t cling to this format. We don’t believe it will be a big problem if it doesn’t convene,’’ Russian Foreign Minister Sergey Lavrov said.
But Harper urged the world not to be fooled by Russian President Vladimir Putin's apparent ambivalence towards the G7's actions.
"The cavalier reaction of Putin is to strut everywhere and shrug off any response; that's just how he handles these things," Harper said.
"Russia's increasing diplomatic isolation ... we don't believe is trivial. A regime does not spend $50 billion on the Olympics if it does not care about its international reputation. This is meaningful action."
The G7 leaders also said they're preparing to "intensify actions" against Russia if Moscow escalates the conflict in southeastern Ukraine any further.
That could include targeting Russia's lucrative energy sector, Harper suggested. White House officials have said U.S. President Barack Obama is prepared to inflict widespread penalties against key sectors of Russia's economy, including its energy industry, if Putin dares move into southeastern Ukraine.
"We know there are a number of vulnerabilities and sensitivities, we know energy's important, and that's why we're determined to continue to work over the long term and to develop a plan that will be effective," Harper said.
"This illegal occupation of Crimea — the reaction is not going to be brief. This is going to be an ongoing pressure to indicate that a large part of the world community is simply never going to accept this."
Earlier Monday, Ukraine told its remaining troops in the Crimean peninsula to leave the Black Sea region because it's too dangerous to remain.
Russian troops are amassing on the southeastern border of Ukraine. There are fears Moscow could use the unrest in the eastern reaches of the country, where there's a large Russian minority, as a pretext for crossing the border.
In an unexpected development on Monday, Lavrov met in The Hague with his Ukrainian counterpart. Their meeting is the highest level of contact between the two countries since Russia made a play for Crimea.
Some European G7 members have been reticent about tougher economic sanctions against Moscow because Europe does so much trade with Russia, and many European economies are still fragile in the aftermath of the 2008 global economic recession.
But German Chancellor Angela Merkel has recently shifted towards the North American stance, reportedly fed up with false assurances Putin gave her about Crimea.
"As long as the political environment for the G8 is not at hand, as is the case at the moment, there is no G8 — neither as a concrete summit meeting or even as a format for meetings," Merkel said before the summit, which took place at the Dutch prime minister's official residence.
The leaders, gathered around a small round table with their countries' flags lined up behind them, joked for the media at the summit before they got down to business — what to do about Russia.
Earlier Monday, Harper said economic concerns will have to take a back seat as the West determines how to respond to Russian aggression.
"Within the context of Canadian foreign policy, we will do what we can to maximize the commercial opportunities for our firms," the prime minister told a roundtable with Dutch business representatives.
"But," he continued, "we will not shape our foreign policy to commercial interests."
When it comes to a global security crisis such as that unfolding in Ukraine, Harper said, "business people have to be aware that there may be risks to them and the government will take those risks, because at those points in times the government's foreign and security policy priorities become paramount."
The summit came shortly after Russia announced a travel ban on 13 Canadian politicians and officials in retaliation for travel and economic sanctions Canada imposed earlier this month.
The list is a mixed bag that includes the Speaker of the Commons, a cabinet minister, MPs noted for their support for human rights, a senator known for her work on Canadian-Ukrainian relations and the head of a Ukrainian-Canadian organization. Some have recently travelled to Ukraine.
The politicians are: Speaker Andrew Scheer; Peter Van Loan, the government House leader; Tory MPs Dean Allison, Ted Opitz, and James Bezan; Liberal MPs Irwin Cotler and Chrystia Freeland; NDP MP Paul Dewar; and Conservative Sen. Raynell Andreychuk.
The officials are: Wayne Wouters, clerk of the Privy Council; Jean-Francois Tremblay, deputy secretary to the cabinet; and Christine Hogan, assistant secretary to the cabinet. Paul Grod, national president of the Ukrainian Canadian Congress, rounded out the list of the banned.
“I was expelled from the Soviet Union in 1979,” Cotler tweeted. “I did not stop fighting for human rights then, nor will I stop now.”
Harper is the only G7 leader who has personally witnessed the devastation in Kyiv and spoken face-to-face with Ukraine's new leadership.
The prime minister has called for a "complete reversal" of Russia's annexation of Crimea and has also warned long and loudly that Putin cannot be trusted. He's also cautioned that Putin's actions will spur similar brazen territory grabs if they go unpunished.
One observer — Ken Brill, former U.S. ambassador to the International Atomic Energy Agency — said while Putin might publicly shrug off an expulsion from the G8, it will privately "rankle" the Russian leader.
Follow Lee-Anne Goodman on Twitter at @leeanne25
Note to readers: This is a corrected story. An earlier version identified Andreychuk as a Liberal.