After the Russian invasion of Ukraine, NATO seemed stronger than ever; it was united, committed and clear-eyed, a stark contrast from the post-Cold War NATO that seemed to have lost its purpose. However, with President Donald Trump’s re-election, the alliance has never seemed more fragile either. NATO’s first shake-up of his second term came when he demanded members pay 5% of their GDP towards defence (an almost untenable number for some members, but it passed nonetheless), then it was jolted again when the President began eyeing Greenland.
Now the President is yet again causing NATO leaders to face an existential crisis. After the US attacked Iran a couple of weeks ago, the US has struggled to keep the ever-important Strait of Hormuz open. As many doubtlessly already know, much of the world’s oil passes through this strait, along with roughly one third of fertiliser and helium, which is an important ingredient in microchip manufacturing. Needless to say, the world is in for a supply shock in virtually all industries over the coming weeks, particularly food.
Although the President snubbed his European allies at the opening of this conflict, his tune has since changed. Upset at allies’ reticence and hostility to the idea of aiding this war, he has questioned whether the US should remain in NATO. Nevermind that NATO is a defensive alliance and did not participate under the NATO flag in either the Korean or Vietnam wars. His foreign secretary Marco Rubio, usually more amiable to Europe and NATO, has repeated this line of questioning.
However, few have assessed what this would look like. For Europe, NATO is the very backbone of their defence, and its dissolution would come at a very fragile time for the continent, but at the same time it would carry dire consequences for the American ability to project power across the world. Furthermore, is it even possible?
Is it possible?
The short answer: no, technically not. Although any member is free to leave NATO provided they give a year’s notice under Article 13, there are domestic hurdles. In the 2023/2024 session, before the President took office, Congress passed a law stating that no sitting president could unilaterally pull the US out of NATO without either 2/3rds of the Senate or an act of Congress. Funnily enough, the bill was cosponsored by then-Senator Marco Rubio himself, but that is neither here nor there. The executive could still try to act unilaterally, as this President is wont to do, but it would likely lead to a costly constitutional fight that runs the risk of backfiring.
However, that is not to say that the President is without options. He could, among milder examples, refuse to meaningfully participate in planning, which could leave members exposed, or signal that Article 5 is conditional (which he already has). He could also withdraw troops or decrease American presence on European soil, something he has already threatened but has notably never acted upon.
These are options that would undermine the long-term viability of NATO, or at least become rust on otherwise functional machinery, if it is not amended. Frustrating, yes, but not life-threatening. However, the real havoc would be wrought should a member be attacked during his presidency. As the supreme commander of the US military, he could simply refuse or slow-walk a military response, effectively killing the alliance. After all, Article 5 only states that:
“The Parties agree that an armed attack against one or more of them in Europe or North America shall be considered an attack against them all and consequently they agree that, if such an armed attack occurs, each of them, in exercise of the right of individual or collective self-defence recognised by Article 51 of the Charter of the United Nations, will assist the Party or Parties so attacked by taking forthwith, individually and in concert with the other Parties, such action as it deems necessary, including the use of armed force, to restore and maintain the security of the North Atlantic area.”
While each member should consider an armed attack on another member as an attack on themselves, thus implying military action in response, it is not actually explicitly stated. President Trump could, for example, drag out the planning process of a response for months, or support the attacked member with a humanitarian response, all depending on what is “deemed necessary.” Surely, it would be the topic of hot debate within the US, but it could take months for Congress or the Senate to force a response. By that time, who could say what damage could be done?
The Ultimate Game of Chicken
Just a little under a year ago, the threat alone would have been enough to make Europe jump toward negotiating with the US. Since then, European leaders and other NATO allies have become keenly aware that appeasement is not a long-term strategy with President Trump. While his first threat made the alliance commit to a 5% spending target on defence from previously more lax members, his threats towards the integrity of NATO have not subsided. Neither did a trade deal stop the President from levying further tariffs, as the EU learned. The Qataris gifted President Trump’s government a plane yet was not warned of the initial strikes on Iran (although the buildup of military presence may have been a clue). In other words, appeasement does not necessarily earn you President Trump’s loyalty. So, why bother?
Europe still has a few cards up its sleeves. They are indeed dependent on NATO, however with Russia still tied up in Ukraine it would seem unlikely they’d open a second front, meaning the most acute risk of a non-committed US during an attack is somewhat mitigated. During the Greenland crisis, several European leaders discussed the possibility of evicting or severely limiting American access to US bases on European soil, something that would be on the table again. Being forced out of Europe, especially during the military operation in Iran, would be messy, costly and above all, somewhat humiliating. Furthermore, access to these bases is a logistical relief to the US military during operations in the Middle East, and logistics do win wars after all.
It comes down to a game of chicken. Europe knows very well that the President can’t unilaterally pull the US out of NATO, and given the current circumstances, don’t see a reason to blink under his threats. President Trump, on the other hand, may be too tied up in Iran to make any other big, geopolitical moves right now. That being said, he is known for his propensity to “flood the zone”, leaving room for uncertainty.
One could certainly see a scenario where the US and their European allies could make a deal in support of Ukraine, at least in order for the US to regain access to their European bases. However, with the amount of money and weaponry required in the Middle East, one could wonder what the US could even spare for Ukraine at this moment. Likewise, there is very little support Europe could provide in Iran that the US do not possess themselves, especially as European militaries and financial institutions are so tied up in supporting Ukraine.
What remains is one very uneasy stalemate that ultimately only proves why NATO must remain united to begin with. If the US was still supporting Ukraine, Europeans may feel more inclined to acquiesce even to President Trump’s wildest whims, and the US would then in turn be in a stronger diplomatic position to influence others in the Gulf to assist as well. Alas, while President Trump’s style of brute-force diplomacy may work well in some cases, it only serves the opposite purpose when people figure out there will be no carrot after the stick.