To prevent a major war, international law must be modernised and strengthened, rather than shrugged off as a casualty of realpolitik. Increasingly, public debate is dominated by the view that international law is good and right so long as it coincides with one’s own interests — and may, or even should, be disregarded if it prevents “evil” powers from being brought to their just punishment or if violations serve one’s own strategic ends. Because of the contempt for international law shown not only by Putin, Khamenei, and Xi Jinping but also by Netanyahu and Trump, it now appears so ineffective that some commentators simply declare it obsolete — a good idea, they suggest, but not fit for real life. In Der Spiegel, the editor-in-chief of Germany’s leading newsmagazine writes that it is a civilisational advance that “evil” heads of state can now be liquidated with minimal collateral damage. All that remains is to clarify who decides what is good and what is evil.

But does the possible liberation of the Iranian people and the region from a horrific regime not justify the use of military force? Who would not be tempted, in such a case, to relegate international law to the background — and who wants to risk, in defending it, being suspected of siding with the butchers of Tehran? Even if, as one must hope, the war ends quickly and produces a less horrific regime, it remains an act of unilateral force in which the United States has not even attempted to assemble an international coalition of support. It is evident that Israel and the US are concerned with eliminating the current regime, weakening Iran as a regional power, and pushing back their imperial competitors China and Russia. This is not an intervention grounded in the human-rights-oriented “responsibility to protect”. The liberation of Iranian men and women is at best a collateral benefit. In the worst case, the result will be state collapse, civil war, flight, and expulsion. In any case, this attack has further lowered the threshold for choosing war as a solution.

Swift victories encourage the hubris that the world can be reordered by military force according to one’s own interests. Brilliant and less brilliant commanders-in-chief — from Alexander the Great to Genghis Khan and Napoleon, all the way to Adolf Hitler — succumbed to this illusion. The “very stable genius” in the White House and his brother in spirit in Tel Aviv risk falling prey to the same temptation. Gaza reduced to rubble, Hezbollah bombed to pieces, the Syrian army decimated, Assad in Moscow, Iran’s nuclear programme in ruins, Maduro kidnapped, Cuba without oil, Khamenei dead, total air superiority over Iran and Lebanon: Trump and Netanyahu seem to succeed at everything. Nothing and no one appears able to withstand their military power. Unlike Putin, whose army has been bogged down in trench warfare for four years, they score one Blitzsieg after another.

Chancellor Merz announces that Germany aims to build the strongest conventional army in Europe and assume leadership responsibility on the continent. One can only play a role, he argues, if one speaks the language of power politics oneself. Historically, military strength has not served Germany well. Reunification — that peaceful stroke of good fortune in German history — was possible because Germany declared in the Two Plus Four Treaty that it would renounce military power politics. An explicit renunciation of nuclear weapons and the halving of the German armed forces served as reassurance to Germany’s neighbours that a reunited, fully sovereign Germany did not intend to speak the language of military power. A peaceful posture was the only, and remarkably successful, strategy for influence and power that remained to Germany after Stalingrad and Auschwitz.

Anyone who believes that the Zeitenwende requires Germany and Europe to secure their future primarily through military strength should state clearly that this, in fact, implies terminating the Two Plus Four Treaty. To field the strongest conventional army in Europe requires more than 370,000 soldiers, and genuine military autonomy is not attainable without nuclear weapons.

In view of Putin’s readiness to use force in violation of international law — but also that of Trump — what is needed is a strengthening of European defence capabilities, not of German warfighting capacity. These capabilities must, however, be conceived and developed in tandem with efforts at confidence-building between adversaries and, above all, with the exploitation of non-military sources of power, influence, and understanding.

The alternative to a coexistence of sovereign states constrained by international law is an arms race that will, sooner or later, culminate in war. Only optimists can believe, given the va-banque policies of the erratic leaders of nuclear powers, that such a new arms race will again end with the peaceful implosion of one of the rivals.

Military attacks are being normalised, justified, or at least accepted as the lesser evil because measures in conformity with international law have failed to stop either terrorism or the human-rights violations of brutal dictators. Even though the interventions of Trump and Netanyahu — not to mention Putin — are not about democracy and human rights, criticism of the lack of enforceability of international law, which is built into the UN Charter but now manifests itself with full force, cannot simply be dismissed. The conclusion that international law should therefore be replaced by national power is, however, not realism but fatalism. No one argues that we should abandon the enforcement of property rights simply because theft occurs anyway.

In practice, states do not always comply with international law. Major powers recognise neither the International Court of Justice (ICJ) nor the International Criminal Court (ICC), and the permanent members of the UN Security Council stand practically above international law, as they can block any decision authorising intervention by using their veto. The lack of will and of power to prevent or punish violations renders international law toothless and ultimately makes it appear superfluous — a purely declaratory, fair-weather exercise.

Those who nevertheless uphold the principles of international law in the face of this reality are accused of being out-of-touch sticklers for principle, naïve do-gooders, or hopeless idealists. Yet it was not do-gooders who drafted the UN Charter after 1945, but the great powers themselves. One can accuse Joseph Stalin, the ruthless Soviet dictator, Harry Truman, responsible for Nagasaki and Hiroshima, Chiang Kai-shek, the butcher of Shanghai, Winston Churchill, the British imperialist, or Charles de Gaulle, founder of the force de frappe, of many things — but not of being do-gooders or naïve.

International law embodies both a long-term maximum and a realpolitical minimum: the ambitious goal of lasting peace among nations, and the minimum aim of preventing another world war. Building on Immanuel Kant’s essay “Perpetual Peace”, its long-term perspective is to end all wars. States are to renounce “their lawless freedom of incessantly waging war” and instead, on the basis of jointly agreed rules, strive for “rational” freedom — that is, a non-violent, sovereign coexistence for all states. This can only succeed if, as Kant puts it, “it so happens that a powerful and enlightened people can form a republic (which, by its nature, must be inclined to perpetual peace), this republic will provide a centre of federative union for other states to join, and thus secure the freedom of states in accordance with the idea of the law of nations and, by further connections of this kind, spread this federation ever further.” At the end of the Second World War, “a powerful and enlightened people” — the citizens of the United States, inspired by the ideas of Franklin Roosevelt — used their overwhelming power in precisely this sense. They were the driving force behind the founding of the United Nations. Confident in their peaceful superiority, they had no reason to fear a peace order. Their relative decline is now causing them to lose this self-assured sovereignty.

After two world wars, the primary interest and goal of the victorious powers was to prevent yet another world war arising from rivalries among great powers. Without this interest, and without humanity’s horror at the devastation of two world wars, there would have been no UN Charter. Its purpose was to ensure that whoever starts a war of imperial conquest is in the wrong from the outset, whatever propaganda is used to justify it. The threshold for using war as the continuation of politics by other means was designed to be raised, especially for the great powers. Perhaps the most important minimal task of international law — already since the Peace of Westphalia, which ended the Thirty Years’ War — has not been to protect the small from the big but to prevent war between the big powers.

There is no civilisational alternative to the effort to embed respect for mutual sovereignty in binding general rules. The alternatives are a world state created by the subjugation of all under a single superpower — neither desirable nor realistic — or mutual surveillance between competing power blocs, oscillating between deterrence and military escalation. The rapid succession of major-power interventions and the constant threat of widening wars increase the risk of a large-scale conflagration. As we are currently witnessing, the transition from local wars to a global one is not abrupt but gradual.

Those who abandon the attempt to strive for common rules and instead believe that all that is needed is to relearn the language of power are turning onto the home stretch toward great barbarism. To talk and write this up as an unavoidable reality of realpolitik is pathetic and, from a European perspective, devoid of a future.

The alliance of middle powers invoked by the Canadian prime minister must now be backed up by action. Europe must demonstrate its capacity to act by transferring national sovereign rights to the supranational level as the basis for peaceful coexistence. Despite everything, Europe is still the most advanced form of a legally structured, peaceful coexistence of equal states. The European Union is the best real-world alternative to neo-imperialism. Europe must pool its regulatory, trade, and defence-policy capabilities, strive for a global alliance of “non-aligned” democratic nations, oppose the arbitrariness of the US, support Ukraine against Putin, and offer people living in authoritarian or semi-authoritarian societies an attractive alternative model of society.

No one who violates international law themselves can credibly defend it. Credibility and reliability are an indispensable asset for international order. An alliance of democratic middle powers can therefore only gain authority and weight if it refuses to participate, directly or indirectly, in wars that violate international law.

In the longer term, the UN Charter and UN decision-making mechanisms should be adapted to new realities. The veto powers will use their vetoes to defend their privilege of blocking decisions at all costs. To circumvent this, one conceivable step would be a voluntary self-commitment by states to comply, regardless of Security Council decisions, with resolutions of the UN General Assembly if these are adopted by 80 per cent of member states representing at least 50 per cent of the world’s population. The alliance of middle powers could launch such an initiative to reform and renew the UN.

One of the most important struggles over whether the world order moves toward war and violence — or whether there is still hope for movement in the direction of civilisation — is currently taking place in the United States. The fate of the world depends to a large extent on the internal power struggle in the US. Despite Trump and the democracy-contemptuous billionaires around him, the US is not yet an authoritarian regime.

International victories strengthen Trump at home, while defeats weaken him. For this reason, the appeasement shown by Europeans in the face of the Ukraine conflict is understandable but nonetheless fundamentally wrong. In this context, it was a mistake for the German chancellor, during his visit to the White House, to respond to Trump’s Spain-bashing not by defending his European partner but by doubling down, stressing that Spain too should spend five per cent of its gross national product on defence.

Instead, the goal must be to offer all those fighting against Trump in the US help and support at every level of social and political life. What happens on the other side of the Atlantic is too important for us to stand by and merely watch.

Effective international law is the civilisational alternative to rearmament and war; it is hard to imagine enforcing it without the United States, or against them. That is why we must not leave Americans alone in their struggle against Trump. This great nation needs the world’s help.