It’s just 5.56 centimeters long — about 2 inches — and only 5.7 millimeters in diameter at its business end. In its most common American variant, it weighs 12.3 grams. It can reach a muzzle velocity of over 3,000 feet per second, and it is designed to penetrate three-eighths of an inch of steel at 350 meters.

In 1980, after decades of development and negotiation, the NATO member states agreed to use this particular cartridge — and it is now one of the most common small-arms munitions in the world. The argument for such standardization is obvious: In combat, being able to share ammunition can make the difference between surviving a firefight and being overrun. The argument against standardization is that should one nation want to deploy another option — a more powerful bullet, for instance — it can’t. At least not within the confines of the alliance.

NATO has been a central pillar of US security policy since the Cold War. In 2016, candidate Donald Trump proposed upending that 70-year consensus, calling the alliance “obsolete” — a statement repeated by President-elect Trump on Jan. 15. But such a claim ignores what’s really lost when such common ventures break apart.


An alliance, like any collaboration, doesn’t work simply because its members agree on a course of action. It requires much more: Standardization of equipment served as a force multiplier for Western armies against the Soviet Union. But when humans succeed in striving toward a common goal, much more than mere common gear is involved: practices, processes, and a shared vision of risk and reward. This cohesion creats powerful intellectual bonds and, over time, lead to the accumulation of knowledge.

Consider the scientific alliance through which a group of men set out to measure the weather.

The story of what made the world modern is often told in heroic terms, tales of grand ideas, or battles, or inventions and inventors. Isaac Newton, Gottfried Leibniz, Galileo Galilei — these are the kind of figures remembered as the leaders of the scientific revolution. But a host of others built an intellectual infrastructure vital to the ongoing advance of science for over three centuries. At the heart of that effort: agreed standards for both material and habits of mind that have propelled the transformation in human knowledge over the last four centuries.


Thomas Tompion, for example, is hardly as celebrated as Robert Hooke, “England’s Galileo.” But he built the first watches driven by the balance spring mechanism that Hooke had invented, which yielded far more accurate time-keeping than prior approaches. Tompion was hugely prolific — his workshop produced roughly 5,500 watches — but perhaps his most wholly original idea had nothing to do with the mechanical side of his designs. From the 1670s forward, Tompion inscribed numbers on each watch and other devices that emerged from his shop, in the first known use of serial numbers.

In the 1670s, neither Tompion nor anyone else produced perfectly replicated devices. Serial numbers were thus not an assertion that each of his watches would measure time to a specific standard of accuracy. Rather, subjecting his creations to the rule of number advanced the possibility of such standardization, providing the first piece of data needed to ensure that one measurement matches another — to be confident a second is a second is a second no matter who is observing and no matter where the observation is taking place.

While this first step toward the standardization of the tools of science was a milestone, it took the development of a common process — shared habits, ways of working — to truly transform the eager curiosity of the 17th and 18th centuries into a revolutionary new approach to knowledge, the one we now call science. In 1705, the Philosophical Transactions of the Royal Society published an article by the philosopher John Locke. It was a modest work, just a weather diary: a series of daily observations of temperature, barometric pressure, precipitation, cloud cover. He was a careful observer, working with the best available instruments, a set built by Tompion himself. On Sunday, Dec. 13, 1691, for example, Locke left his rooms just before 9 a.m. The temperature was 3.4 on Tompion’s scale — a little chilly, but not a hard frost. Atmospheric pressure had dropped slightly compared to the day before, 30 inches of mercury compared to 30.04. There was a mild east wind, 1 on Locke’s improvised scale, enough to “just move the leaves.” The cloud cover was thick and unbroken — which is to say it was an entirely unsurprising December day in the east of England: dull, damp, and raw.


On the pages of the Royal Society’s journal, though, these perfectly banal details coalesce into a more significant advance. Locke described his methods and approach, what instruments he used; how he used them; when, each day, he made his measurements; everything anyone would need to interpret his data or to observe on their own. That made Locke’s report more than a mere list of facts about local weather patterns in Essex. It described a method, a process that could produce new knowledge.


The creation of standards, for equipment and for process, was and remains central to what makes science work as an institution, an enterprise, and not simply as a siloed exercise in individual curiosity. It was designed that way from the start: Locke got inspired to tackle meteorology when Robert Hooke published a call in the Royal Society’s journal, seeking volunteers who would buy instruments, calibrate them, and take weather data every day.

To put this move into the jargon of the NATO alliance, Hooke set out to forge the scientific revolution’s own force multiplier. His army of citizen scientists committed to a shared use of the apparatus of inquiry — thermometers and the like — and to a social compact: how they would collect new knowledge (in scientific reports) combined with the obligation to share, to publish, all to come up with a picture of the natural world that no one of them could possibly have assembled on their own.

A US soldier with the 101st Airborne Division fires an AT-4 as Combat Outpost Nolen on the outskirts of the village of Jellawar came under Taliban attack on September 11, 2010. PATRICK BAZ/AFP/Getty Images

Fundamentally, NATO works in much the same way, however much its scale and complexity exceed Hooke’s network of weather watchers. The NATO round is an example of the more obvious parallel, the need to ensure that everyone’s tools work together. A common cartridge hits the highest level of cooperation — it is truly interchangeable. Much of the time, though, NATO allies look for interoperability, ways to ensure different systems can still function on the same battlefield, just as researchers from the 17th century onward must work out how to compare observations acquired on different instruments.


Such interoperability depends on a huge number of often seemingly small choices. Tanks need regular refueling, for example, but NATO allies deploy several different types of tanks. So resupply operations have to bring not just the fuel, but various filters, too, so that one tanker truck can serve every piece of armor in need. When a battery dies? To get a jump from a European tank to an American one, soldiers must use a variety of cables and adapters. Such details matter — in action, lives may depend on having the right electrical connector — and given the amount of equipment used to fight modern war, there is a lot of specific hardware that has to be identified, agreed on, and deployed. But even so, this is the easier side of what it takes to make NATO go.

The more complicated and more important task: forging a common approach to thinking and communicating across the alliance. Common material is important, but what’s vital is a common methodology, a common language. Sometimes, it’s purely vocabulary at issue. “You have to be proficient in language — in English — to have a common perspective — particularly in combat,” says Colonel Ivan Mikuz, formerly a NATO strategic planner, now the Slovenian defense attaché in Washington.

Just as essential, and more difficult to achieve, NATO over the decades has developed common habits of thought, the procedures its personnel use to work together on every level from small unit operations to strategic planning. “You have to find agreement in a structured way,” Mikuz says. “Doctrine and tactics that are commonly shared.”

This plays out from the top down, where strategic planning is (or at least is supposed to follow) a shared formal decision making process, complete with checklists and a sequence of problems to be solved. The same enforced common approach extends to combat. When a wounded soldier needs to be evacuated from the battlefield, for example, there is a standard nine-line form that must be filled out — in English. The form tells the medical team where they need to go, how to contact those in need, the severity of the wounds, whether enemy troops are nearby, and so on. “Interoperability is much more than technical. It connects people on many levels,” Mikuz says. When those connections fray, “it can cost lives.”

Cartridges lie in the sand as Canadian Task Force Kandahar soldiers take part in a shooting exercise at Camp Nathan Smith on June 7, 2010. Ed Jones/AFP/Getty Images

None of this is to say that collaboration within NATO works perfectly. “Since 1989, the fall of the Berlin wall, NATO has atrophied,” says US Army Colonel Mark Aitken. War today moves quickly, he says, and NATO hasn’t kept up — not on the hardware, nor the human part of collaboration. Member armies use a variety of digital systems to control artillery fire, for example, and many of the systems don’t talk to each other. On the human side — different NATO members take different approaches to making sure a fire mission will hit what it’s aimed at, and nothing else. The US standard says that it should take no more than three minutes to make sure the downrange area is clear and fire a shell. In a recent multinational exercise, “the fastest we got,” the colonel says, “was just under an hour.”

That failure illustrates just how much work goes into making even long-established alliances function effectively. Arguments for preserving NATO tend to focus on the larger issues of international security. Aitken emphasizes that leaving NATO would damage US relations with Europe, risking the destabilization of the continent. One retired military officer puts it this way: “What’s the cost of walking away from the alliance? 40,000 guys. That’s what the Europeans put into Afghanistan — and that’s 40,000 Americans that didn’t have to show up.”

Behind such strategic questions, though, there’s this to consider: Should the alliance shatter, all the social infrastructure that allows people to collaborate will break with it. On the most obvious level, different nations could, for example, begin using weapons that don’t fire the NATO round. There isn’t an infinite supply of jumper cable adapters. More deeply, the human systems, all the formal and informal lines of communication NATO’s officers and enlisted forces have worked out over the decades can fall apart much more quickly than they can be remade. How long would it take before a wounded soldier dies en route to care because the habits embedded in that nine-line form no longer hold?

On April 12, after a meeting with the NATO secretary general, President Trump announced, “I said it was obsolete. It’s no longer obsolete.” While the ease with which Trump stuck his back-flip doesn’t yield much confidence, for now it seems the United States intends to remain in the alliance. But even as a thought experiment, recognizing what truly is required to sustain complex human collaborations suggests how much there is to lose.

John Locke died in October 1704, seven months before his weather diary appeared in print. In what can thus be read as late, if not last words, he there allowed himself to dream of what might come from his having “indulged his Curiosity.” His intellectual heirs, he wrote, could accumulate enough data in enough places so that “several Rules and Observations concerning the extent of Winds and Rains, [and could] be in time established, to the great advantage of Mankind.”

Over the three centuries since those words appeared, we have done just that, and so much more. We abandon the kinds of connections that produce such accomplishments at our peril.

Thomas Levenson is a professor of science writing at MIT and an Ideas columnist. His latest book is “The Hunt for Vulcan.”