In the aftermath of the Second World War, with much of Europe in ruins, millions of people displaced, the horrors of the Holocaust a recent memory and an uneasy peace splintering the European continent, the North Atlantic Treaty Organization was founded.

NATO tied the security of European democracies to American military power in order to deter then Soviet expansion and aggression. On May 6th, 1955 West Germany joined NATO and the Soviet Union retaliated with the Warsaw Pact coalition eight days later. For decades, Europe was fractured by ideology, economic systems and outlook.

Today, NATO remains the most important alliance in the world. Unlike other international bodies and forums, NATO has proven its ability to influence global affairs by not only shaping military outcomes but also buttressing a stable world order by virtue of its very existence. While the European Union looks increasingly shaky, and the prospect of a Brexit adding to the instability, NATO is a rock upon which diplomacy and military planning remains constant.

Predicated on consensus, NATO, as a political forum and a military organization, engages its members with three pillars: Collective defence, cooperative security and crisis management.

For Canada, NATO provides a forum to express Canada’s position on the most important international security issues. Be it Afghanistan, Iraq, Europe, the Seas surrounding the Horn of Africa or the ongoing war against extremists, NATO coalitions enable Canada to project Canadian power and Canadian values abroad.

Canada’s position is in stark contrast to that of certain American politicians: We need more NATO, not less of it. In a past life, I was a passionate advocate for NATO expansion. I still am. The inclusion of Georgia and Macedonia into NATO should occur in the near term and I look forward to one day welcoming those two nations sharing the protective umbrella of NATO.

The exclusion of Ukraine in the Alliance was to our collective shame. With a concentrated push, Ukraine’s path to membership would have united large swaths of that nation and what most see as the illegal Russian invasion of Crimea would not have occurred.

As it is, Russia’s Prime Minister has declared a new Cold War against NATO and Russian rhetoric has once again regressed to a tone of antagonism. NATO, with it's combined and interdependent strength, has acted as an effective deterrent to many forms of invasion, aggression and violence and will continue to do so.

The present challenge is that all three of NATO’s pillars are stressed. NATO’s collective defence is being challenged by an uneven, unfair burden sharing where the United States pays over 70% of the costs and, worse still, only five member states are able to muster the minimal spending target for defence.

While contributing mightily in recent efforts such as Afghanistan, Canada has a tainted legacy of meeting that minimal standard of 2% of GDP dedicated to National Defence. NATO’s cooperative security is being challenged by the incoherence of needs, perspectives and expectations.

It is easy for the Alliance to trust in close partners like Australia and a number of Scandinavian partners. Much harder is how to navigate relations with unpredictable rogue states and non-state actors, enforcing non-proliferation of weaponry and cyber warfare tools and identifying enemy combatants in counter insurgency operations. NATO’s crisis management abilities rest with the organization’s preparedness and readiness to act.

Article 5 of NATO’s founding charter reads, “an armed attack against one or more of them in Europe or North America shall be considered an attack against them all.” Canada has traditionally played a key role in alliance operations with military efforts in the former Yugoslavia in the 1990s, in Afghanistan for over a decade and now in Iraq. Canada has also provided leadership within the alliance in drafting a new strategic concept and preparing for disaster relief operations.

NATO is having its next leaders summit in Warsaw this July against the backdrop of an unpredictable - and often surreal - American presidential election. While some have questioned the future of NATO, I believe Canada and its closest allies need to prepare a concise narrative about the importance of the Alliance to the Euro-Atlantic area and our partners around the world.

That narrative needs to clearly state our commitment to the alliance and to working to deliver collective defence, cooperative security and crisis management. We need to back that commitment up with action and money. That means a commitment to funding our militaries with predictable and stable increases as agreed at the Wales Summit. Canada can and should lead that effort. For if we were to lose NATO, Canada’s well-earned position as a trusted partner in international security and stability as well as our ability to affect positive change in the world would be adversely and irreversibly affected.

- Peter MacKay is a former Attorney General and Minister of Justice, Minister of National Defence and Minister of Foreign Affairs. This article reflects his personal views.