NATO leaders meeting here have been quick to brand Russia an aggressor state, intent on dominating Eastern Europe.

Earlier this year, Prime Minister Stephen Harper called Russia “militaristic” and “imperialistic” while Foreign Affairs Minister John Baird suggested the country’s recent actions in Ukraine were akin to those of Nazi Germany.

What isn’t being discussed here in any great depth, however, is how NATO’s own actions – its expansion right up to Russia’s borders – has played a key role in sparking the confrontation over Ukraine.

“They’ve backed Russia into a corner and of course the Russians are none too happy about that,” explained Joe Bissett, Canada’s former ambassador to Yugoslavia, Bulgaria and Albania, who also lived in Russia for five years. “The U.S. broke their promise to Russia that NATO would not move eastward and the result is the situation today.”

Since the end of the Cold War, NATO has expanded its membership to include a number of countries once allied with the Russians such as Poland, Romania, Lithuania and Estonia. The alliance, and its troops, now sits on Russia’s borders.

A U.S. plan to deploy missile interceptors in Poland and the Czech Republic has also angered the Russians. NATO and western leaders say Russia has nothing to fear from the move east.

But the Russians have been warning since at least 2008 that NATO’s expansion was causing deterioration in its relations with the West. That year Russian leader Vladimir Putin noted that his country viewed the “appearance of a powerful military bloc” on its borders “as a direct threat” to its security. Claims by NATO that the expansion wasn’t directed at boxing in Russia were not enough, he added. “National security is not based on promises,” Putin warned.

That same year, NATO ignored Russia’s concerns and moved to further expand the alliance to include Ukraine and Georgia, ex-Soviet republics.

Germany, however, stepped in to block that initiative because it was worried such a move would cause the further deterioration of relations with Russia.

Over the last five years, Russia has continually accused the West of breaking its promises made after the fall of the Iron Curtain. Mikhail Gorbachev said in 2009 he was given assurances NATO would not expand “as much as a thumb’s width further to the East.”

Putin has pointed to the U.S. missile interceptor system to be installed in Europe as further evidence of Western betrayal. He has said it is designed to target Russia’s nuclear force and has rejected U.S. assurances its role is to shoot down rockets launched from Iran.

NATO has dismissed Russian concerns outright.

The alliance’s expansion helps spread democracy and economic growth, a NATO official told the Citizen on Thursday.

And no documents exist to support Russia’s claims that NATO made a promise it would not expand into its sphere of influence, the alliance added in a July 2014 statement.

“To divert attention away from its actions, Russia has levelled a series of accusations against NATO which are based on misrepresentations of the facts and ignore the sustained effort that NATO has put into building a partnership with Russia,” NATO noted.

In March, as the situation in Ukraine heated up, Putin warned that Russia was fed up with what he characterized as betrayals by the West. “They cheated us again and again, made decisions behind our back, presenting us with completed facts,” he said in a speech. “That’s the way it was with the expansion of NATO in the East, with the deployment of military infrastructure at our borders. They always told us the same thing: ‘well, this doesn’t involve you.’”

Putin’s actions in seizing the Crimea and taking a hard line in his dealings with the West are extremely popular among Russia’s public. In July, Putin further warned that NATO was intent on continuing its expansion, building up its forces in Eastern Europe, including the Black Sea and Baltic Sea.

A senior Canadian government official rejects the argument that NATO’s expansion contributed to the current crisis. “That sounds like Ukraine or some of these other countries should be considered buffer zones for the Russians,” the official said. “They’re not. They’re independent democratic countries with the same rights to security and self defence that other countries want.”

Peggy Mason, who served as Canada’s disarmament ambassador under Prime Minister Brian Mulroney, said there are various arguments on both sides of the debate about whether the West reneged on its promise not to enlarge NATO to Russia’s borders.

“What I think is not open to as much debate is the fact that this is a very strongly held Russian perception, which the West should have taken far more seriously, instead of asserting our good intentions and the rightness of our position and telling the Russians they have nothing to worry about,” said Mason, president of the Ottawa-based Rideau Institute.

She noted the Conservative government’s foreign policy on Ukraine is that one side, Russia, is entirely wrong and the other side, Ukraine and the West, are entirely right.

“Not only is this approach rarely factually defensible, given the many sides of most issues, it also misses the point that, to find solutions, we have to be able to take into account what others perceive as their legitimate security concerns,” she said.