The prospect of a “NATO without the United States” appears to have shifted from a theoretical discussion to a critical strategic concern for European leaders, with US President Trump’s plans to push for Greenland, a semi-autonomous territory of Denmark, a NATO member country that is also a NATO country, to become America’s 51st state.
The US president has said that Greenland is vital to US national security and confirmed that talks with NATO are underway regarding the territory.
Europe disagrees with Trump’s plans – A historic rupture
But this is not accepted by the other 31 members, which, apart from Canada, are all from Europe. It was unthinkable for them to accept the scenario of a NATO member country occupying the territory of another country by military means. So far, Poland has warned that US threats over Greenland could “end the alliance.”
Other European members such as the UK, Germany and France are discussing a “NATO military mission” to Greenland to protect it from another member – the US – marking a historic rupture. Already, soldiers from France, Germany and other European countries have begun arriving in Greenland to help bolster Greenland’s security after a “fundamental disagreement” in talks involving Denmark, Greenland and the United States.
France has reportedly sent 15 soldiers and Germany 13. Norway and Sweden are also sending. The mission has been described as a reconnaissance exercise, with troops planting the European Union flag in Greenland as a symbolic act. The first French soldiers are already on their way, and “more will follow,” French President Macron said. French authorities revealed that soldiers from the country’s mountain infantry unit were already in Nuuk, the Greenlandic capital.
Germany is said to have deployed a 13-man reconnaissance team to Greenland. Denmark has already increased its military presence in Greenland and plans to deploy more troops.
NATO without the US
All of this has led to a peculiar situation in global geopolitics – the prospect of a NATO without America – that was previously unthinkable. Of course, over its 76-year history, the North Atlantic Treaty Organization, or NATO, has faced its fair share of crises, but none as serious as the one it is facing today.
NATO alliance is cracking
As things stand, since Trump returned to power in early 2025, his policy of reducing the American share of the NATO budget and his different stance on responding to the ongoing war in Ukraine had already damaged at least two key features of the alliance’s collective defense commitment – the “shared understanding of threats” for NATO members and the “indivisible security among members.”
But Trump’s obsession with Greenland could now lead to the fragmentation, if not the dissolution, of NATO, as many experts express. If NATO is truly dissolved or disbanded, without the United States being outside of it, what will happen? Are Europeans ready to live without the American security guarantee?
The London-based International Institute for Strategic Studies (IISS), a leading think tank on global security, political risk, and military conflict, published a report titled “Defending Europe without the United States: Costs and Consequences.” This report assessed the financial costs and defense industry requirements for a European NATO to defend against a future Russian threat in the event that the United States withdraws from NATO.
The US accounts for 65% of NATO military spending
It is worth noting that the US accounts for around 65% of NATO’s total military spending. According to the IISS report above, to replace the supposed US conventional capabilities committed to the Euro-Atlantic theatre, European states would have to invest significant resources on top of existing plans to enhance military capability.
Taking into account one-off procurement costs and assuming a 25-year life cycle, the IISS estimates that this cost would amount to around $1 trillion. More radical approaches to defence investment and defence spending levels approaching Cold War levels – where spending “averaged” above 3% – will be required.
Europe is becoming more militarized
Of course, on the positive side, the report says, several European countries and the European Union have already begun to pave the way for increased defense spending and a better investment environment in the defense sector. However, it remains to be seen whether the political will to achieve the necessary spending levels will be evident in all European nations, given the limited fiscal space for many governments.
The report by the International Institute for Strategic Studies (IISS) also noted that European allies will face challenges in the defense industry. While procurement orders have accelerated in the land sector, there is less urgency in the naval and aerospace sectors, with little additional investment in production capacity.
This is problematic, as large-scale provision of air and sea platforms would be a key requirement if Europe were to replace the US military’s contribution in these areas. Given the defence industry’s challenges related to contracting, financing, labour shortages, regulation and security of supply, the IISS estimates that, within the next decade, Europe’s defence industry will struggle to replace many of the US capabilities, particularly in the air and naval sectors.
European countries simply do not have the military and technological resources to immediately replace what the United States has supplied. A US withdrawal would leave European allies “not fighting quietly” due to the loss of US-operated systems:
Active military personnel: Apparently, right now, 30 NATO members have 1.5 million active military personnel, if the US leaves NATO… the Europeans need to add 300,000 new soldiers to replace current US capabilities. Importantly, this transition period requires US support.
Information & Command: The US provides the bulk of airborne early warning (AWACS), strategic intelligence collection and battlefield surveillance.
Logistics & Enablers: Key capabilities such as air-to-air refuelling, strategic airlift and space assets are almost entirely dependent on US resources.
Integrated Air Defense: NATO’s current air and ballistic missile defense systems are based primarily on American technology and command structures.
A serious blow to nuclear deterrence
However, the most significant loss that the Europeans will face in a NATO without America is nuclear deterrence. Only France and the United Kingdom possess nuclear weapons, with their combined total (about 515 warheads) dwarfed by the 5,000 that the United States supposedly has in its arsenal. After all, Russia, which the Europeans see as the greatest threat to European security, also possesses over 5,000 nuclear warheads.
The United States will also lose
Incidentally, if the United States withdraws from NATO, the United States will also clearly lose.
First, The United States will then no longer have access to its 31 permanent bases in Europe. These facilities, especially Ramstein in Germany, are critical to operations and the projection of American power in the Middle East and Africa.
Second, decades of seamless information sharing through NATO protocols would be disrupted in the event of a US-Europe split, limiting American “eyes and ears” across the entire Eurasian region.
Third, arms sales to Europe, so critical to American defense manufacturers, would be seriously jeopardized. It has not been realized that since the Russian invasion of Ukraine, American arms sales to Europe have increased dramatically.
Arms Value $117.9 Billion
The value of US foreign military sales (FMS) to Europe has increased significantly, reaching approximately $68 billion in 2024, a huge increase from the average of $11 billion between 2017 and 2021.
In fact, US arms exports reached an all-time high of $117.9 billion in fiscal year 2024, with much of this funding provided by European allies and partners.
Clearly, a “divided” Europe pursuing massive military modernization to achieve self-sufficiency and strategic autonomy will pose significant risks to the market share of US defense companies.
Considering all this, one could say that a separation of Europe from the United States within NATO, which some describe as a “transatlantic divorce,” would be deeply painful for both sides.
