Major disruptions to maritime chokepoints always send ripples through the entire global network. Like voltage through an electrical grid, maritime commerce will shift to the path of least resistance, with nations forced to redistribute security assets accordingly. The current conflict with Iran is testing this concept in real time — and US government planners need to be paying attention, both for short-term and long-term planning.
Maritime canals, straits, and capes are not independent waterways with unchanging risk profiles. They are, in fact, interconnected points in a system within the global maritime network on which international commerce relies. Disruption in one location redistributes traffic worldwide, altering shipping costs, delivery timelines, and global capacity.
In more extreme circumstances, this creates risk calculations that are very different from the steady state. This also creates dilemmas for governments regarding required force distributions to either maintain a specific chokepoint or protect national shipping interests.
Firms are already considering the impacts of conflict adjacent to the Strait of Hormuz, through which 20 percent of the world’s petroleum sails. A near-term return to the status quo may produce short-term uncertainty in shipping, with only marginal impacts on global commerce. However, the term “marginal” can still include billions of dollars, as shown by the March 2021 Ever Given grounding in the Suez. Conversely, a replay of the 1984-1988 Tanker Wars, or complete closure of the waterway, paints a very different picture.
In light of current events, leaders need to understand how the network has changed and be prepared to act accordingly. To define chokepoint risk, consider six factors:
- Navigation (are there underwater obstructions or dangerous currents)
- Environmental (high waves or storms)
- Geopolitical (are adjacent nations stable and in control)
- Criminal (is there a high incidence of piracy)
- Density (is this a high traffic waterway)
- Economic activity (is this a regional or global economic corridor)
From a risk perspective, navigation and environmental risks are largely static and rarely affected by activity at other locations. Geopolitical and criminal (piracy) risks tend to drift toward adjacent chokepoints, while traffic density and economic activity quickly ripple throughout the entire system.
Looking closest to the closure, Bab al-Mandeb, located near Yemen, may expect an increase in lawlessness. Already poorly governed, regional frictions are sure to spread to Yemen, and those transiting the lower Red Sea should expect increased threats from both piracy and warring factions. There may be a decrease in traffic as vessels no longer need to move between the Mediterranean and the Persian Gulf, but the Red Sea remains an important corridor for commercial and military traffic between Western nations and the Middle East. Consequently, while the current fight is through Hormuz, it is necessary to maintain maritime patrols in the vicinity of the Bab al-Mandeb and the Gulf of Aden.
Similar traffic reductions will decrease risk through the Suez, Gibraltar, and Strait of Malacca. It is not expected that political uncertainty will show any increased instability along these three routes. Accordingly, it is reasonable to accept risk in these areas and rely on local nations to maintain these thoroughfares.
Where policy makers must firmly fix their gaze is the Turkish Straits. Ongoing conflict in the Black Sea Region (BSR) has already increased the risk between the Black and Aegean seas. Globally recognized as a wheat corridor between Ukrainian fields and the world, it is less appreciated that the BSR provides over 3 percent of global petroleum reserves, a figure likely to skyrocket in volume and value amid major market shifts. Expect to see a 5 percent increase in maritime traffic transiting through Istanbul.
Since the 1936 Montreux Convention, Turkey, whose military nearly doubles that of any European NATO ally, has deftly managed its control of the straits to stabilize geopolitical tensions in the region. But the heightened importance of the strait underscores the need for other interested parties to work together to support continued commerce. Bulgarian and Romanian forces, exempt from Montreux restrictions, must work with their Turkish NATO allies to monitor Black Sea activity, while the US 6th Fleet maintains vigilance in the Eastern Mediterranean and Aegean Seas.
The heightened importance of the waterway makes it an attractive target for malign actors, although Russia is less of a threat since much of the oil is theirs. Ankara is aware of these risks and should consider hosting regional exercises with NATO allies as a show of unified deterrence.
Further from the Iranian coast, there are also distant risks to consider. As shipers look elsewhere, the the Panama Canal, Kattegat, and the Cape of Good Hope will see increased traffic, as well as increased risk profiles.
Denmark and Sweden should increase their Kattegat presence operations in conjunction with the Baltic Sea nations. There will be an increase in the already sizable energy shipments through the straits. However, the region’s strong governance mitigates the need for any increase in US presence.
Panama is more susceptible to disruption due to greater regional volatility and narrow pounds throughout. It is in US interests to divert forces either at sea or along the canal to ensure uninterrupted operations. The cost of closure would further disrupt commerce and drastically impede global force management options. Cape of Good Hope traffic should see little impact due to strong South African governance and limited geographic constraints.
Not every shipping lane will see a change from the conflict, of course. Shipments to and from the Gulf are unlikely to benefit from a polar transit. Similarly, little impact is expected through the Lombok or Straits of Magellan. And that’s good news for the US and its allies, given how much water there is already to worry about on a global scale.
Maritime chokepoints do not operate in isolation; they are interconnected nodes in a dynamic, risk-bearing network where disruption at one point propagates across routes, costs, and timelines worldwide. The current tensions near the Straits of Hormuz illustrate how geopolitics, traffic density, and environmental conditions collectively reshape global commerce. While some routes may experience temporary relief or reduced activity, others may see sudden surges in traffic or risk, underscoring the need for robust, forward-looking risk management and coordinated policy responses.
A nuanced, network-aware assessment that accounts for shifting traffic patterns, alternate routes, and the cumulative impact on energy supply chains allows governments to focus forces efficiently: maintaining in the Eastern Mediterranean, Gulf of Aden, and the Panamanian Isthmus, while accepting reduced concentration in the Western Mediterranean, Danish Straits Northeast Passage, and western Pacific straits. It also allows industry to maintain resilience in a fluid, interconnected maritime regime.
Michael Kidd is a US Navy Supply Corps captain and instructor at the Eisenhower School for National Security and Resource Strategy. He writes on issues surrounding military and logistics risk. Disclaimer: The views expressed are those of the author and do not necessarily reflect the views of the National Defense University or Department of War.