Any top 10 ranking of international achievements since 1945 would include the European Union (EU). Celebrating its unity every May 9, the EU in its various iterations has preserved the peace and promoted prosperity in a continent that for centuries was the cockpit for global conflicts.

Canada is bound to Europe through ties of history, family and sacrifice. Our collective security is enshrined through NATO and we recently negotiated the Comprehensive Economic and Trade Agreement (CETA).

This month, we commemorate the many cords that bind us in ceremonies marking the 70th anniversaries of the Battle of the Atlantic and Victory in Europe Day. Prime Minister Stephen Harper observed that Canadian “commitment, innovation and professionalism” in the Second World War generated “international recognition for our country and immense national pride.”

If the United States was the arsenal of democracy, Canada was the aerodrome, training thousands of Commonwealth fliers. Canadians built and sailed many of the ships that won the Battle of the Atlantic. On this battle, Winston Churchill said, hinged, “everything elsewhere on land, sea and air.” By war’s end, the Royal Canadian Navy was one of the world’s largest, growing from 3,300 men and 13 ships to 95,000 men and women and 428 ships.

Ceremonies in recent days across the Netherlands remember the more than 7,600 Canadians who died in its liberation. The tulips blooming today on Parliament Hill are the gift of a grateful Dutch nation and, later this month, King Willem-Alexander and Queen Maxima will visit Ottawa.

The EU continues to be an experiment – political, economic, social and cultural – in federalism. Federalism is a system of government in which Canadians are also invested, especially in the practice of pluralism.

There are faults and flaws with the EU: too much bureaucracy; economic disequilibrium between south and north; the tensions of balance between national and supra-national sovereignties evidenced in the emergence of anti-EU, nationalist-populist parties; and, the threat of exits by Greece (“Grexit”), through financial default, or Britain (“Brexit”), through Prime Minister David Cameron’s promised referendum.

The European experiment has faced many challenges: the Cold War that threatened global catastrophe; dissolution of the former Soviet Union and the tragedies that befell the Balkans; the recent Great Recession with effects still plaguing much of southern Europe; the boatloads of refugees from the Middle East and Africa now crossing the Mediterranean.

But the European Union endures and the refugee inflow is testament to the continuing attraction of the EU’s liberal and democratic virtues.

There is a line of new applicants for EU membership. The Ukrainian crisis was sparked in part by Ukrainian desire for closer association with the EU rather than the Russian-dominated Eurasian Economic Union. Last month, Albanian Foreign Minister Ditmir Bushati was in Ottawa and received Canadian endorsement for its EU bid.

The EU’s economic partnerships continue to broaden. It is negotiating a Transatlantic Trade and Investment Partnership with the United States. The public debate on investor state dispute settlement threatens to sideswipe our CETA, now in post-negotiation legal scrub and translation.

We need to re-engage with the EU’s Commission, Council, parliamentarians and member states to assuage concerns, highlight the mutual benefits and ensure that there is no backsliding. An energetic diplomatic campaign should be complemented with visits by ministers and the business community.

Let’s utilize our various inter-parliamentary relationships. The European legislators within the NATO Parliamentary Association are influential and the Canadian delegation should be making the case for CETA at its spring session in Budapest this week.

The case for Canada begins with the more than 100,000 Canadians who died during two world wars, many of whom are buried throughout Europe. Canada’s current deployment includes RCAF fighter jets in Central and Eastern Europe; HMCS Fredericton recently completed exercises in the Baltic. Trainers in Ukraine could also help our Baltic allies.

The generation that fought the Second World War and then created global and regional institutions, rooted in liberal internationalism, is now passing. So, too, is the international consensus that holds these institutions in place.

This past weekend Russia staged its biggest-ever military parade in Red Square to mark Victory Day. Standing with President Vladmir Putin were Chinese President Xi Jinping, Zimbabwe’s Robert Mugabe, Cuba’s Raul Castro and Venezuela’s Nicolas Maduro. Mr. Putin reiterated his criticism of NATO and the United States. Later this week, China and Russia conduct joint naval exercises in the Mediterranean.

We take for granted continuing peace and prosperity, starting with our deeply rooted transatlantic partnerships. But without a commitment to activist diplomacy, backed up by muscular collective defence, this century could be as difficult as the last.