The NATO summit in Madrid will make landmark decisions for Europe’s security. Putin’s war has welded NATO together. However, differing national preferences about the future course of defense could soon call the newfound unity into question.

The widespread failure of the Russian military in the first weeks of the war surprised most Western analysts. At the same time, renowned experts are now warning of false conclusions: a war by Russia against NATO would certainly look different and be prepared differently than the campaign against Ukraine. This raises the question of whether NATO has overestimated Russia’s military capabilities in recent years, as does the question of Russia’s military reserves.

There is also uncertainty about Russia’s ability to compensate for the material losses it has suffered. Western sanctions have led to predictions of the imminent demise of the Russian military and its gunsmiths, which rely on Western technology imports. In fact, the manufacture and import of high technology for Russia will become more difficult in the future.

Nevertheless, Moscow will probably continue to be able to buy semiconductors and chips in China. The financial resources for this are available due to increased energy prices.

At the same time, nobody knows what will happen if Donald Trump or a similarly nationalist representative of his party moves into the White House at the end of 2024. While Europeans are now spending significantly more on defense as a result of the war, that doesn’t change America’s long-term strategic interest in focusing on China. The war in Europe actually only distracts from that. A President Trump could well leave the Europeans out in the rain.

At the same time, the ability of the European NATO members to deploy significant contingents of troops for defense in Eastern Europe in an emergency is currently very different. Germany in particular would probably only be able to do this in a few years, despite the 100 billion special fund. This would also require closely coordinated European processes for the procurement of armaments. But that just doesn’t exist at the moment.

The speed with which Russia would be able to renew its military would in turn have a direct impact on Europe’s future security. The European allies might have only a very small window of opportunity to organize their own security.

It is also unclear where the future contact zone between NATO and Russia will run – in the worst case on the western borders of Ukraine or even in neutral Moldova. The uncertainty about the further course of the war has a direct impact on the future geographical focus of NATO defence.

There are also different defense preferences. While future NATO member Finland has already ruled out permanent NATO bases on its territory, countries like Poland, the three Baltic states and Romania want large, permanently stationed NATO units. Hungary’s populist President Orbán, on the other hand, is trying to balance alliance solidarity with maintaining his special relationship with the Kremlin. This raises the question of how stringent the future NATO strategy can be.

For NATO’s future strategic concept, these uncertainties mean squaring the circle. On the one hand, it must provide military security for the eastern members of the alliance, taking into account different preferences and uncertainties in terms of geography and Russian military strength.

On the other hand, it has to recognize that important NATO countries, such as Germany, are currently not (yet) in a position to take on a large part of the defense tasks in Eastern Europe, while America’s domestic political zigzag course makes strategic planning more difficult.

Since 2014, NATO has been pursuing a “tripwire” strategy towards Russia. In the event of a Russian attack, for example on the Baltic States, the small, locally stationed NATO troops would not be able to stop Russia. However, their sheer presence and the fact that almost every NATO country participates in the associations would have involved the entire alliance within a few hours. A second and third wave of NATO supplies would then have brought larger units into combat.

After Russia’s invasion of Ukraine, the allies agreed to set up similar small formations in Bulgaria, Hungary, Romania and Slovakia. In turn, the existing battalions in Estonia, Lithuania, Latvia and Poland were reinforced. Germany will set up a brigade headquarters in Lithuania. The rest of the brigade is to be based in Germany and regularly flown into the country for training purposes.

NATO Secretary General Jens Stoltenberg recently also announced “more armed forces on a higher level of readiness and specific armed forces intended for the defense of certain alliance partners”. Taken together, the result is a reinforced “trip wire” and an expansion and faster availability of troops moving up. Nevertheless, not only the Estonian Prime Minister Kaja Kallas calls for “warfare capacities” for NATO to “be able to strike back immediately”.

With its rather cautious course so far, NATO is on the right track. In order to also strengthen the responsibility of the Europeans in the future, the new edition of a military concept from the Cold War offers itself: the so-called “spider” in the “web”.

Using Lithuania as an example, this could mean that the Lithuanian military – responsible for the “net” – would be equipped with shoulder-launched anti-tank ammunition, man-portable drones and mobile artillery platforms for modern ammunition in order to be able to act as quickly as possible in a network of scattered, camouflaged and fortified firing positions .

Instead of buying expensive ships for the Navy, land-based anti-ship missile batteries could bolster sea defenses. At the same time, larger European allies – the “spider” – would have to ensure that sufficient, safe equipment was stored locally for rapid replenishment and invest in logistics, air transport capacities and anti-aircraft defense for the successor forces to be provided by them.

Such an approach would have several political advantages. European allies, including Germany, would assume primary responsibility for defending NATO’s eastern flank without having to commit forces today that they do not currently have or cannot afford to deploy.

This would give Europeans time to invest further in national armed forces – ideally within the framework of a harmonized European procurement system. At the same time, the Europeans would relieve the United States of some of its burdens. This would not only be an argument should Donald Trump return.

While large, permanently stationed and heavy formations on the border with Russia would be vulnerable as ideal targets for a Russian first strike, the “spider” and “web” model would reduce this risk.

At the same time, a threatening security dilemma with Russia would be reduced, since the NATO units stationed in the contact zone would not be large enough to be able to actively attack Russia. After all, such an approach would also keep the door open to arms control should Russia ever signal that it is interested in strictly mutual and verifiable arms limitations.