Pax Americana is over. The rest of the Western alliance will have to pick up the burden of protecting peace

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Michael Ignatieff teaches history at Central European University in Vienna.

In five short months as President, Donald Trump has accomplished what the Russians and Chinese never succeeded doing in 80 years: He’s splintered the Western alliance.

When the remnants of that alliance met at the G7 summit in Canada this week, Mr. Trump was (at least briefly) in the room, as he will be at the NATO summit in The Hague at the end of the month. But the real questions his allies are asking among themselves are: How do we defend our territory now that America has walked away? How do we keep the international economy open now that America is retreating inside its economic fortress?

Canada’s defence and economic challenges, like those of its allies, are two sides of the same coin.

We can’t sustain rising defence expenditures if our economic productivity lags our competitors. We can’t fix our productivity problems if our cross-border trade is hobbled by tariffs, and if our economic partners are forced to copy Mr. Trump’s protectionist approach.

As Mr. Trump demands his allies step up on defence, his economic policies are making it harder for those allies to rise to the challenge.

Whether this is by malevolent design or careless incompetence no longer matters. What matters is how Canada and its allies respond.

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Many countries in the alliance, Germany, Britain, France, Denmark, Canada included, are boosting their defence expenditures to levels not seen since the height of the Cold War.

Countries close to the Russian border – the Baltic states and Poland – have raised military spending to five per cent of GDP, while others, such as Hungary, appease Putin. Countries with nuclear weapons, such as Britain and France, must decide whether to replace the American nuclear deterrent in Europe with deterrence of their own, extended to the eastern neighbours of Russia.

Meanwhile, in the far east, the Japanese and South Koreans are considering whether to acquire nuclear weapons if America draws down its military commitments in their region. And Taiwan is turning itself into a porcupine to deter the Chinese, as they can’t be sure the Americans will defend them against a Chinese assault.

In the Middle East, America’s traditional role in balancing rivals and deterring conflict is over. As a result, the Israeli strikes on the Iranian nuclear program make nuclear proliferation in the region more likely, not less.

Egypt, Saudi Arabia and the Gulf States will be looking at the strikes and wondering whether they should be arming themselves with nuclear weapons too, if the Americans are no longer holding Israel back.

Outside the ring of fire that is the Middle East, countries like Canada must spend more to recruit and retain members of their armed forces, even if they are uncertain about which weapons they will equip their forces with.

Ukraine’s battle for survival has transformed modern war, drastically increasing the importance of drones, unmanned reconnaissance assets, and cyber and digital weapons. Every country is trying to anticipate what new weapons and force configurations best prepare them to fight the next war, not the last one.

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These aren’t questions that can be left to elites, policy wonks and specialists. We need public debate, and the people need answers if they are going to support their governments through a period of potentially revolutionary change.

To earn buy-in on defence spending, for example, the public needs to understand what threat their military is protecting them from.

In the Baltics and Poland, it may be a direct invasion; farther afield, in Canada, the threat may be military penetration of our Arctic defences, as well as domestic challenges like spying, cyber interference in public and private digital systems, and attempts to subvert our elections.

The public will want to understand the nature of the threat and want to know that their tax dollars are being spent the right way. In a post-Pax Americana world, every Western country’s procurement strategy will cut back on dependence on U.S. defence industries and, as a result, U.S. controls on weapons use. This will be expensive.

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Building up their own domestic defence industries will create jobs at home among these allies, but modern states have a poor record in managing defence procurement wisely. There’s always a risk that defence expenditure will starve a country’s necessary welfare expenditure on health, pensions and social care, or drive up its debt to unsustainable levels, or both.

The people living in alliance countries, Canada included, have enjoyed 80 years of peace, and have developed settled expectations about pensions, health care, equity and justice; Canada’s constitutional doctrine of “peace, order and good government” has committed Liberal and Conservative governments alike to meet these expectations. The very distinctiveness of the European and Canadian social model depends on it.

Maintaining what makes Canada distinctive while we rearm is not going to be easy. Our government will have to accomplish three very difficult tasks at the same time: re-equipping our militaries, rebuilding our productivity so we can sustain our social model, and sustaining alliances now that Americans have walked away.

Alliance membership once answered the question of who we were committed to defend, as Article 5 of the North Atlantic Treaty committed countries to risking everything to defend each other. Once America backs away from that commitment, what remains for the rest of us? Do we defend only our own homeland?

That is the Trump doctrine. If this self-interest becomes the mantra for each of America’s former allies, it will be impossible to guarantee global security in a world where China and Russia have territorial designs on their neighbours.

Countries maintain alliances because they know they can’t defend themselves or their way of life alone. And for the first time in 80 years, leadership on sustaining these alliances will have to come from Europe, Canada and Japan – not from the United States.