President Donald Trump is furious at the unwillingness of America’s European allies to aid the U.S. in reopening the Strait of Hormuz — so angry, in fact, that he is calling the continued usefulness of the alliance into question. “NATO wasn’t there when we needed them, and they won’t be there if we need them again,” Trump fumed in an all-caps Truth Social post after a Wednesday meeting with NATO Secretary-General Mark Rutte. He added a gratuitous jab at Denmark, “Remember Greenland, that big, poorly run, piece of ice!!!”

Trump’s anger at NATO has been festering for weeks. On March 26, the president wrote (again in all caps), “NATO nations have done absolutely nothing to help with the lunatic nation, now militarily decimated, of Iran. The U.S.A. needs nothing from NATO, but ‘never forget’ this very important point in time!”

In addition, President Trump is reportedly considering ways to “punish” the NATO members he believes showed insufficient loyalty during the war by relocating U.S. forces from those countries to the territory of countries that proved more supportive.

Trump does not have unilateral power to withdraw the U.S. from NATO. The 2024 National Defense Authorization Act forbade the president from “suspend[ing], terminat[ing], denounc[ing], or withdraw[ing] the United States from the North Atlantic Treaty” without the advice and consent of the Senate. But he can begin a conversation about NATO’s purpose, some 77 years after its creation, and that is just what President Trump has chosen to do.

For starters, the president does have grounds for frustration with NATO, which Secretary of State Marco Rubio, as usual, presented in the most sympathetic light. “Unfortunately, we are going to have to reexamine whether or not this alliance that has served this country well for a while is still serving that purpose,” he said, “or is it now become a one-way street where America is simply in a position to defend Europe, but when we need the help of our allies, they’re going to deny us basing rights and they’re going to deny us overflight.”

The worst offender in this regard was Spain, which refused to allow U.S. planes involved in the Iran war to use its airspace. Spain is also the only NATO member that has not committed to spending 5% of GDP on defense. Additionally, Italy briefly blocked American use of an air base in Sicily for the operation, and France only allowed the U.S. to use a base in France when the U.S. guaranteed that only planes not used in the Iran strikes would land there. Germany has reportedly also made Trump’s “naughty list” after top German officials criticized the war.

But, while this makes the case for reform or rebuke, it does not clearly lead to complete withdrawal. In a Wednesday interview on CNN, Rutte admitted that “some” NATO members “failed” to live up to their obligations, but argued there were still strategic reasons for the U.S. to remain in the alliance.

“When it comes to NATO, it’s there to protect the United States,” he maintained. “The U.S. needs a secure Atlantic and a secure Arctic and a secure Europe to stay safe here in the U.S. mainland … and to be this platform of power projection for the United States. So, what the U.S. did with Iran, they could do because so many European countries lived up to those commitments.”

In other words, the reason why the United States is able to project power so far from its own shores, Rutte argued, is that NATO’s existence prevents the U.S. from having to worry about military threats nearer at hand.

Of course, any discussion of NATO’s purpose should examine the aims which its inaugural treaty sets forth. The Preamble identifies several goals, which include:

• A “desire to live in peace with all peoples and all governments”;
• A determination “to safeguard the freedom, common heritage and civilisation of their peoples, founded on the principles of democracy, individual liberty and the rule of law”
• A will “to promote stability and well-being in the North Atlantic area”; and
• A resolution to unite “for collective defence and for the preservation of peace and security.”

To condense these phrases into a soundbite, NATO was created to pursue peace, prosperity, and security for Western civilization and its (small-“l”) liberal values. Its basic purpose is therefore not far removed from the Trump agenda.

The articles of the Treaty then match these goals. In Article 1, member nations commit to resolve international disputes “by peaceful means” and “to refrain in their international relations from the threat or use of force.” This was a rejection of the warlike imperialism of World War II’s Axis powers.

Article 2 committed the parties to “strengthening their free institutions” and “promoting conditions of stability and well-being.” This article distinguished NATO ideologically from the Soviet Union and its satellite states. Indeed, the April 4, 1949 treaty was largely created to safeguard the remaining free nations of Europe — America’s allies — against the ever-expanding communist menace.

Later articles expand upon the theme of common defense. Article 3 commits members to “maintain and develop their individual and collective capacity to resist armed attack,” while the well-known Article 5 stipulates that such “an armed attack against one or more of them in Europe or North America shall be considered an attack against them all.”

Significantly, these aims and requirements make NATO a fundamentally defensive treaty. NATO is not a total military alliance to engage in any war that any member chooses. It only applies when peaceful members are attacked by aggressive neighbors. And, as the name suggests, it only applies to a defensive zone covering the continents that border the North Atlantic, Europe, and North America (although various provisions extend that to include the Mediterranean, Turkey, and once-French Algeria).

In effect, NATO acts as a secure fence, guarding the backyard of America and the entire West. It is not a vehicle to other destinations, but it does serve a useful purpose, at least to the extent that Americans value our home security and the guarantee of our Western heritage. We may justly critique the groundskeepers who fail to maintain their part of the fence. We may censure those gatekeepers who will allow in any riff-raff to spoil what we worked so hard to create. But it would be foolish to un-fence the entire backyard in response to these problems and limitations.

To that point, Solomon counsels, “The vexation of a fool is known at once, but the prudent ignores an insult” (Proverbs 12:16). In the present instance, it may be wiser to address the problems with NATO in closed-door sessions, rather than airing every grievance on social media. But that is not President Trump’s usual style; we shall see whether, on this point, Trump’s usual style can coerce the results he seeks.