The United States has long played a leadership role in NATO, the most successful military alliance in history.
The U.S. and 11 other countries in North America and Europe founded NATO in 1949, following World War II. NATO has since grown its membership to include 32 countries in Europe and North America.
But now, European leaders and politicians fear the United States has become a less reliable ally, posing major challenges for Europe and, by implication, NATO.
This concern is not unfounded.
President Donald Trump has repeatedly spoken of a desire to seize Greenland, which is an autonomous territory of Denmark, a NATO member. He has declared that Canada, another NATO member, should become “the 51st state.” Trump has also sided with Russia at the United Nations and said that the European Union, the political and economic group uniting 27 European countries, was designed to “screw” the U.S.
Still, Trump – as well as other senior U.S. government officials – has said that the U.S. remains committed to staying in and supporting NATO.
For decades, both liberal and conservative American politicians have recognized that the U.S. strengthens its own military and economic interests by being a leader in NATO – and by keeping thousands of U.S. troops based in Europe to underwrite its commitment.
Understanding NATO
The U.S., Canada and 10 Western European countries formed NATO nearly 80 years ago as a way to help maintain peace and stability in Europe following World War II. NATO helped European and North American countries bind together and defend themselves against the threat once posed by the Soviet Union, a former communist empire that fell in 1991.
NATO employs about 2,000 people at its headquarters in Brussels. It does not have its own military troops and relies on its 32 member countries to volunteer their own military forces to conduct operations and other tasks under NATO’s leadership.
NATO does have its own military command structure, led by an American military officer, and including military officers from other countries. This team plans and executes all NATO military operations.
In peacetime, military forces working with NATO conduct training exercises across Eastern Europe and other places to help reassure allies about the strength of the military coalition – and to deter potential aggressors, like Russia.
NATO has a relatively small annual budget of around US$3.6 billion. The U.S. and Germany are the largest contributors to this budget, each responsible for funding 16% of NATO’s costs each year.
Separate from NATO’s annual budget, in 2014, NATO members agreed that each participating country should spend the equivalent of 2% of its gross domestic product on their own national defense. Twenty two of NATO’s 31 members with military forces were expected that 2% threshold as of April 2025.
Although NATO is chiefly a military alliance, it has roots in the mutual economic interests of both the U.S. and Europe.
Europe is the United States’ most important economic partner. Roughly one-quarter of all U.S. trade is with Europe – more than the U.S. has with Canada, China or Mexico.
Over 2.3 million American jobs are directly tied to producing exports that reach European countries that are part of NATO.
NATO helps safeguard this mutual economic relationship between the U.S. and Europe. If Russia or another country tries to intimidate, dominate or even invade a European country, this could hurt the American economy. In this way, NATO can be seen as the insurance policy that underwrites the strength and vitality of the American economy.
The heart of that insurance policy is Article 5, a mutual defense pledge that member countries agree to when they join NATO.
Article 5 says that an armed attack against one NATO member is considered an attack against the entire alliance. If one NATO member is attacked, all other NATO members must help defend the country in question. NATO members have only invoked Article 5 once, following the Sept. 11, 2001, attacks in the U.S., when the alliance deployed aircraft to monitor U.S. skies.
A wavering commitment to Article 5
Trump has questioned whether he would enforce Article 5 and help defend a NATO country if it is not paying the required 2% of its gross domestic product.
NBC News also reported in April 2025 that the U.S. is likely going to cut 10,000 or more of the nearly 85,000 American troops stationed in Europe. The U.S. might also relinquish its top military leadership position within NATO, according to NBC.
Many political analysts expect the U.S. to shift its national security focus away from Europe and toward threats posed by China – specifically, the threat of China invading or attacking Taiwan.
At the same time, the Trump administration appears eager to reset relations with Russia. This is despite the Russian military’s atrocities committed against Ukrainian military forces and civilians in the war Russia began in 2022, and Russia’s intensifying hybrid war against Europeans in the form of covert spy attacks across Europe. This hybrid warfare allegedly includesRussia conducting cyberattacks and sabotage operations across Europe. It also involves Russia allegedly trying to plant incendiary devices on planes headed to North America, among other things.
A shifting role in Europe
The available evidence indicates that the U.S. is backing away from its role in Europe. At best – from a European security perspective – the U.S. could still defend European allies with the potential threat of its nuclear weapon arsenal. The U.S. has significantly more nuclear weapons than any Western European country, but it is not clear that this is enough to deter Russia without the clear presence of large numbers of American troops in Europe, especially given that Moscow continues to perceive the U.S. as NATO’s most important and most powerful member.
For this reason, significantly downsizing the number of U.S. troops in Europe, giving up key American military leadership positions in NATO, or backing away from the alliance in other ways appears exceptionally perilous. Such actions could increase Russian aggression across Europe, ultimately threatening not just European security but America’s as well.
Maintaining America’s leadership position in NATO and sustaining its troop levels in Europe helps reinforce the U.S. commitment to defending its most important allies. This is the best way to protect vital U.S. economic interests in Europe today and ensure Washington will have friends to call on in the future.
John Deni is Research Professor of Joint, Interagency, Intergovernmental, and Multinational Security Studies, U.S. Army War College.
The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.
© The Conversation
22 Comments
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TaiwanIsNotChina
In addition to potentially causing defeat overseas, closing bases can result in the bases never being able to be reopened under a patriotic administration.
bass4funk
I'm not concerned, I doubt that will ever happen
TaiwanIsNotChina
NATO decently kept most of its troops away from its Eastern Flank prior to Putin's War.
mikeylikesit
NATO is an expression of the post-WW2 Pax Americana. NATO has existed essentially behind the might of the American dollar and U.S. military. Without the tens of thousands of U.S. soldiers parked in Europe for most of the past century, Europe would likely have continued on the pattern of new major wars every 20-30 years. Every other nation in NATO is essentially a vassal state in all but name. Iraq, Libya, and elsewhere have felt the brunt of NATO’s force, but the alliance has been powerfully effective at keeping internal peace.
America’s and Europe’s interests today steadily diverge. Europe wanted the Euro to compete with the dollar. They got it, with the independence of having their own reserve currency, and now they find themselves potentially facing a divorce from America.
Ultimately, however, any break by America from NATO will be less about Europe’s actions and more about America’s ability to project power. Europe is likely to face a “look to your own defenses” moment from the empire as America repositions globally and militarily. America is broke and can’t keep exerting power over every corner of the globe.
Cephus
"Europeans concerned U.S. will withdraw support from NATO; Americans should be, too"
NATO or no NATO changes nothing, any more fear mongering news?
virusrex
What part of the article can you demonstrate is false or exaggerated?
Because if you can't then it means it is not valid to call it fear mongering, rational people do not fear information, only those that have personal beliefs disproved feel fear when exposed to that information.
Cephus
"What part of the article can you demonstrate is false or exaggerated?
Because if you can't then it means it is not valid to call it fear mongering, rational people do not fear information, only those that have personal beliefs disproved feel fear when exposed to that information."
A circular dogma deserves no answer because it is the answer by itself.
Cephus
"But now, European leaders and politicians fear the United States has become a less reliable ally, posing major challenges for Europe and, by implication, NATO."
The US have mysteriously become less reliable ally for calling more defense spending on NATO? For how long the US citizen will shoulder the bill? If giving a break to the US tax payers is what makes the nation less reliable so be it.
virusrex
There is nothing circular about the text you quote, and it is obviusly not dogmatic when it is even described the conditions where it does not apply. That those necessary conditions are not met means that you yourself recognize your criticism is invalid. It is not that you don't answer the rebuttal, but that you can't argue against it so you have no other recourse but to concede it is valid.
Nothing mysterious about it, being openly aggressive and combative against allies have the obvious consequence of becoming less reliable (to say the least). Much more if it takes the side of Russia in a conflict.
TaiwanIsNotChina
Still Putin's War.
JJE
No, it isn't.
A number of very senior administration officials have gone on the record describing it as provoked.
In a rare lightbulb moment, even loopy Kellogg demonstrated an inkling of intelligence just yesterday in a public speech, by accurately describing this as a "proxy way".
TaiwanIsNotChina
I think we can safely discount those statements as being supplied by the Kremlin.
It can be a proxy war and also a war for Ukraine's survival.
1glenn
Trump is not doing what most Americans want him to do, in regards to NATO or Ukraine.
Primusinter
Firstly, not 30% (Zelensky said 35%, as he wrote in his official channel), but 3%. That is not 40 but less than a dozen (in the official statement of the Armed Forces of Ukraine, the figure has already been corrected to 12). JT, is your goal to mislead your readers or what?
Primusinter
Secondly, 6,000 frozen bodies of dead Ukrainian soldiers, with documents and expertises, will arrive at the border next week in order to return them to their relatives for burial. 6000 is an official statement, which, of course, Taiwan does not believe. Well, let's him not believe it. For 6,000 dead men, Ukraine must pay more than two billion dollars to the relatives of the victims (15 million hryvnias for each, as Zelensky promised by his decree when he mobilized them for the war). Ukraine does not want to accept these 6,000 bodies! Watch Ukrainian talk shows, what ordinary Ukrainians are saying there. Zelensky has already called Russians idiots for this gesture of goodwill, for 6,000 bodies. But that's not the point. Ukraine does not have 2 billion dollars to pay them to the relatives of the deceased soldiers. Dear American taxpayers, get ready to empty your wallets.
bass4funk
Wrong! He is doing exactly what Americans want him to do and that is to stay out of the conflict as much as possible, keep it limited
GuruMick
Just on Trumps "Golden Defence Dome', will it cover the Hawaiian Islands ?
Or American Samoa.?
Or are some American places more worthy of defence ?
deanzaZZR
The economy and population of the EU is many times the size of Russia. If they collectively cannot protect themselves all by themselves they are doing something wrong.
deanzaZZR
If Trump is calling the shots Hawaii will not be protected, nor will California, New Jersey or any other solidly blue state.
TaiwanIsNotChina
The EU hasn't been preparing for conventional war since WW2 like China's dog russia.
Peter14
Do we really want Western Europe to be building thousands of nuclear weapons to compete with Russia? Conventionally with much effort they can match and out produce Russian weapons but Russia has the largest nuclear arsenal in the world and only the US comes close to matching that. China is already ramping up nuke production and North Korea simply wont stop its stockpiling a growing nuclear armory.
It is not America that is unreliable, it is Trump. No other US leader from either party has ever shown Trumps unreliability towards NATO, and after him I would expect the normal bipartisan attitudes to the critical importance of NATO to North America and European security to return.
Trump is the weak link for NATO and America. He is played like a fiddle by Putin, who has Trump erroneously believing that Putin is his "good and close friend". He is not. Putin manipulates Trump at every contact, and will continue to do so, playing on Trumps greatest weak spot, his ego.
HopeSpringsEternal
Trump's pulling out MANY US forces from Europe soon, reason why all other NATO Members now finally busy $spending on defense. Trump's not going to commit any 'backstop' to Ukraine either, Europe on their own.
US European military umbrella "free lunch" is over and now Europe must deal with the consequences of under investment for decades while manipulating the Biden Admin into the Ukraine proxy war with Russia etc.