As the U.S.-Iran war has turned the Strait of Hormuz into a strategic pressure point, one of the world’s most important maritime chokepoints now sits under the shadow of disruption, coercion, or outright closure.
Commercial traffic faces rising danger, markets are bracing for prolonged disruption, and even if the war ends in some form of negotiated settlement, Tehran may still see value in keeping its ability to threaten, restrict, or selectively control passage through the strait as a lasting source of leverage.
However, ironically, more than a year before this latest crisis erupted, the Pentagon quietly launched a program that now looks less like a speculative research effort and more like an early attempt to solve exactly this problem.
Launched by the Defense Advanced Research Projects Agency’s (DARPA) Tactical Technology Office in May 2025, the initiative, “Pulling Guard,” set out to rethink how ships are protected in contested waters.
In solicitation documents, DARPA proposed a more scalable alternative to billion-dollar warships for escorting commercial traffic through chokepoints: semi-autonomous, commercially operated escort systems intended to shield vessels from swarming asymmetric threats.
“The global economy relies on efficient and predictable operation with maritime shipping providing the majority (over 75%) of all goods,” DARPA writes. “Large vessels accomplish most bulk transport, transiting between known ports and frequently through chokepoints, which renders them vulnerable to attack by pirates and terrorists in peacetime and hostile nation-states during armed conflict.”
Read today, that final line carries a striking weight. What DARPA framed as an enduring yet manageable risk has, in the Strait of Hormuz, become an immediate and defining feature of modern conflict.
The vulnerability of large commercial vessels moving through narrow chokepoints is currently playing out in real time, with global consequences for energy markets, supply chains, and the balance of power at sea.
In that sense, the warning embedded in Pulling Guard’s rationale now feels less like background context and more like a prophetic diagnosis of the crisis unfolding today.
A New Model for Maritime Defense
Historically, the U.S. Navy has deployed high-end assets, such as guided-missile destroyers and carrier strike groups, to protect shipping lanes. However, DARPA’s own assessment is blunt: “The massive number of ships and routes used by those ships renders the use of combatant escort or long-range defense systems untenable at the scale required.”
And that reality is now playing out in real time.
Instead of warships, Pulling Guard envisions a distributed network of smaller, semi-autonomous escort platforms that can accompany commercial vessels through dangerous waters.
These systems are designed to be flexible, detachable, and commercially owned. Rather than permanently arming merchant ships, which can create legal and port-access complications, the escort system would attach after departure and detach before arrival.
This allows ships to remain compliant with international regulations while still receiving protection at sea.
The concept is also built on a “protection as a service” business model, in which private companies operate and maintain the systems, while the U.S. military provides oversight and lethal authority when required.
That hybrid structure shows a broader shift underway in defense thinking—one that blends commercial innovation with military command-and-control.
Pulling Guard systems are intended to be semi-autonomous, not fully autonomous. DARPA says remote military operators would remain in the loop for engagement authority, supervision, and other high-consequence decisions, including lethality decisions.
Pulling Guard for the Threats of Today’s Wars
If the Strait of Hormuz crisis has highlighted anything, it’s the growing effectiveness of asymmetric maritime threats.
Small, fast, and often unmanned, these systems are cheap to build but difficult to defend against, especially in large numbers. Iran, like Ukraine in the Black Sea, has demonstrated that relatively inexpensive platforms can threaten much larger, more expensive assets.
DARPA’s program is explicitly designed around that reality.
The Pulling Guard concept focuses on detecting and defeating “small surface threats” using passive or low-probability-of-detection sensors, allowing the system to operate in contested environments without revealing its position.
Once a threat is identified, the system can engage with a range of existing government-provided munitions, including guided rockets, short-range missiles, and other low-cost effectors.
Program targets call for the ability to defeat coordinated attacks with high probability, while keeping false alarms low and maintaining continuous overwatch for days at a time.
In other words, the system is being designed to handle exactly the kind of swarm-style attacks that have become increasingly common in modern maritime conflict.
Scaling Protection in a Crowded Ocean
One of the most important elements of the Pulling Guard program is scale.
There are simply too many ships, too many routes, and too many potential threats for traditional naval escort models to keep up. DARPA’s solution is to create an ecosystem, not just a platform.
The program is structured around multiple components, including sensing systems, autonomous targeting, and a modular platform that can integrate different technologies over time.
This modular approach is designed to ensure that the system can evolve alongside emerging threats, rather than becoming obsolete as adversaries adapt. It also allows different companies to develop different parts of the system, fostering competition and innovation.
Perhaps most importantly, the system is designed to be deployable at scale. Rather than a handful of high-end ships, Pulling Guard envisions a large number of relatively low-cost escort systems distributed across global shipping routes.
In a place like the Strait of Hormuz, that could mean the difference between protecting a few vessels and protecting all of them.
From Concept to Capability
The program itself is ambitious, but also tightly structured.
Pulling Guard was launched as a 39-month effort, with an initial phase focused on iterative design and testing, followed by a second phase aimed at integration, manufacturing, and real-world demonstration. The end goal is a commercially viable system that can transition into operational use.
“The desired end state of the program is to have two complete and functional demonstrator Pulling Guard systems that can then be transitioned into commercial production and service delivery by the performers,” DARPA writes.
Unlike many traditional defense programs, Pulling Guard is explicitly designed for use in both peacetime and conflict under the ‘protection as a service’ model. In essence, DARPA envisions commercially owned systems that can generate income while remaining available for wartime escort missions.
Pulling Guard – a Program Ahead of Its Time
What makes Pulling Guard particularly striking today is how closely it coincides with the challenges now unfolding in the Strait of Hormuz. A year ago, it was a forward-looking concept aimed at future threats. Today, it looks like a potential solution to a present crisis.
The U.S. Navy’s ability to escort every vulnerable vessel through contested waters is increasingly limited. At the same time, adversaries are doubling down on low-cost, high-impact tactics that exploit those limitations.
Pulling Guard offers a way to expand protection without expanding the fleet. To counter swarms without matching them ship for ship. And to bring commercial innovation into one of the most critical missions in global security.
In that sense, Pulling Guard increasingly looks like a program ahead of its time. The problem it was designed to solve has arrived faster than the technology meant to address it. While DARPA has already begun moving forward—with companies like Saronic selected in early 2026 to help develop modular, autonomy-enabled escort vessels—the program itself remains on a deliberate timeline.
Under its current structure, Pulling Guard remains a multi-phase development effort. The first operational systems are not expected to transition to commercial service until early 2029. That means unless the program is significantly accelerated, it will arrive too late to shape the current crisis.
That gap highlights a familiar tension in the speed of emerging threats versus the pace of developing and fielding new capabilities. Pulling Guard may represent a viable answer to the vulnerabilities now being exposed in the world’s most critical shipping lanes, but for now, it remains just out of reach.
“By pioneering this new approach, Pulling Guard is forging a new paradigm in global maritime security to keep the seas safe and open for military and commercial customers,” DARPA writes. “Our approach is central to current global economic issues; therefore, collaboration between military and commercial operators is essential for maximum impact.”
Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan. Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com