The Houthis, Operation Prosperity Guardian, and Asymmetric Threats to Global Commerce
The MOC
July 18, 2024
U.S. military officials and policymakers face a difficult choice in the Bab el-Mandeb: commit to a massive and sustained investment in maintaining open sea lanes by permanently neutralizing the Yemeni Houthi movement or allowing the international community to bear the burden of increased shipping costs. The geopolitical consequences of this decision will not be limited to the Arabian Peninsula and—in either case—the Houthis’ asymmetric blockade of the Red Sea and Gulf of Aden is setting a massive precedent in the modern history of naval warfare.
Maritime piracy was once a ubiquitous impediment to the trading ambitions of sovereign powers, going as far back as the classical era and possibly predating it. Indeed, the first major articulation of American foreign policy following independence was in response to the Barbary pirates’ threats to American commerce. Since the development of mature blue water navies in the nineteenth century, however, great powers have consolidated control of the sea lanes and largely eradicated threats posed by groups without the capacity to deploy large nautical vessels. A key element of the hegemonic power of the British Empire in the nineteenth century was London’s role as the guarantor of uninterrupted global commerce, a role passed down to the United States in the twentieth and twenty-first centuries.
While previous non-state actors such as Somali pirates have targeted individual shipping vessels, eliciting an international response, no non-state actor before the Houthis has been able to credibly threaten to blockade a global shipping lane. The Houthis have called this hegemony into question using weapons that cost pennies on the dollar compared to those needed to counter them. The disparity in costs between the Houthis and their nation-state competitors marks a paradigm shift in U.S. naval primacy. The consequences of non-state actor holding effective veto power on maritime commerce against the most powerful navy on the planet will not be limited to the Bab el-Mandeb.
While the economic ramifications of the Houthis’ attacks since December 2023 were first localized among shipping companies, ultimately, they will be felt by manufacturers and consumers around the world. Operation Prosperity Guardian—the U.S. Central Command task force organized to neutralize the Houthi threat to sea lanes—is a crucial test of whether the United States will continue to serve as the primary guarantor of global trade.
The Houthis first started attacking vessels in the Red Sea as far back as March 2015, utilizing a rudimentary network of sea mines and relatively aged anti-ship missiles captured from Yemeni government forces along with military, materiel, and technical assistance provided by Hezbollah and the Islamic Revolutionary Guard Corps. On the whole, these attacks were ineffective at stopping the flow of commerce; however, they successfully imposed costs on the Saudi-led coalition then fighting the Houthis, forcing them to devote resources to demining key waterways and directly countering Houthi attacks on shipping. By utilizing simple, inexpensive weapons to attack defenseless targets—i.e. commercial shipping—the Houthis discovered how to impose disproportionate costs on Saudi Arabia, their allies, and the wider Western world.
Despite deploying some of the most advanced air defense systems in the world, Saudi forces struggled to keep up with a drumbeat of Houthi missile and drone attacks since the conflict began in 2015. This was in part due to a lack of effective interceptors designed specifically to combat small, low-flying threats, but also to the mixed nature of Houthi attacks, which often employed a variety of threats simultaneously. The interceptors that did prove effective in combating Houthi attacks also turned out to be some of the most expensive, costing Saudi Arabia hundreds of millions of dollars in advanced munitions to mitigate low-level attacks by small drones and cruise missiles. This is gross overkill for weapon systems like the MIM-104 Patriot and AIM-120 AMRAAM, both of which were designed to intercept advanced aircraft and cruise and ballistic missiles of the type only a nation-state can afford to field. Expending these counter-munitions at a high rate to deal with low-level threats leaves a gap in air defenses which can then be exploited by more accurate, expensive, and advanced weapons. The evolving asymmetric war between air defense and inexpensive airborne munitions has also been seen in the ongoing war in Europe, where both Ukraine and Russia have struggled to economically intercept airborne threats.
Today, Operation Prosperity Guardian is the United States’ single longest naval engagement since the Second World War, supported by the extended deployment of some of the world’s most advanced warships. Though these ships are designed to project power and defend the United States and its allies from peer- or near-peer level threats, the Houthis are once again keeping a better equipped opponent on the back foot. Container shipping through the strait has dropped 90 percent since their attacks began in October 2023, with dozens of major maritime carriers sending ships the long way around the Cape of Good Hope instead of risking an attack, resulting in millions of dollars in additional costs for each vessel. The overall impact on global trade is substantial and rising. If Operation Prosperity Guardian is unable to restore free transit of the Bab el-Mandeb, the impact on American credibility will be substantial.
The ongoing Houthi attacks on commercial shipping occur at a time when advanced air defense resources are at a premium for the United States and its allies. Russia’s barrage of missiles and drones against Ukraine (oftentimes utilizing similar Iranian-designed munitions as the Houthis) and the threat of China in the Pacific has already placed strain on the inventory and availability of U.S.-made air defense munitions. The crisis in the Middle East post-October 7th, 2023 has seen the expenditure of even more advanced air defense munitions in an effort to protect Israel and ships passing through the Red Sea. So many missiles have been fired by the Navy against Houthi drones and missiles, that the Navy has requested hundreds of millions of dollars in additional funding to restock its missile inventory, further raising concerns about the relative cost disparity between advanced air defense missiles and the low-level airborne threats employed by the Houthis. While the exact cost of the individual weapons employed by the Houthis remains unknown, it is almost certainly a fraction of the cost of the weapon systems, vessels, and support staff required to intercept them as part of Operation Prosperity Guardian.
This stark disparity has ushered in a paradigm shift of strategic importance: either the United States finds a way to stop the threat here, or other groups will replicate the Houthis’ strategy elsewhere, undermining U.S. command of the seas. The success of Prosperity Guardian is of paramount importance to continued U.S. strategic dominance. While prior counterinsurgency operations against irregular forces in the Middle East proved vexing, the underlying assumption of American deterrence capabilities via superior financing and firepower was never seriously called into question by these campaigns. If a group with a fraction of the financial and material resources of the United States can wage a successful, sustained campaign of area denial against the United States, allies and adversaries alike will take note. American naval primacy—and therefore its superpower status—will be imperiled.
Cameron Keyani is the Director of Analysis at Artis International. He has a background in OFAC sanctions evasion investigations for federal law enforcement and in the private sector, and completed his Master’s thesis on IRGC Quds Force hybrid warfare in 2019.
Cameron Henley is an Analyst at Artis International. He holds a Masters of Law and Diplomacy from the Fletcher School at Tufts University, where his capstone research was focused on non-state actor used of unmanned aerial vehicles.
The views expressed in this piece are the sole opinions of the author and do not necessarily reflect those of the Center for Maritime Strategy or other institutions listed.
Center for Maritime Strategy
U.S. military officials and policymakers face a difficult choice in the Bab el-Mandeb: commit to a massive and sustained investment in maintaining open sea lanes by permanently neutralizing the Yemeni Houthi movement or allowing the international community to bear the burden of increased shipping costs. The geopolitical consequences of this decision will not be limited to the Arabian Peninsula and—in either case—the Houthis’ asymmetric blockade of the Red Sea and Gulf of Aden is setting a massive precedent in the modern history of naval warfare.
Maritime piracy was once a ubiquitous impediment to the trading ambitions of sovereign powers, going as far back as the classical era and possibly predating it. Indeed, the first major articulation of American foreign policy following independence was in response to the Barbary pirates’ threats to American commerce. Since the development of mature blue water navies in the nineteenth century, however, great powers have consolidated control of the sea lanes and largely eradicated threats posed by groups without the capacity to deploy large nautical vessels. A key element of the hegemonic power of the British Empire in the nineteenth century was London’s role as the guarantor of uninterrupted global commerce, a role passed down to the United States in the twentieth and twenty-first centuries.
While previous non-state actors such as Somali pirates have targeted individual shipping vessels, eliciting an international response, no non-state actor before the Houthis has been able to credibly threaten to blockade a global shipping lane. The Houthis have called this hegemony into question using weapons that cost pennies on the dollar compared to those needed to counter them. The disparity in costs between the Houthis and their nation-state competitors marks a paradigm shift in U.S. naval primacy. The consequences of non-state actor holding effective veto power on maritime commerce against the most powerful navy on the planet will not be limited to the Bab el-Mandeb.
While the economic ramifications of the Houthis’ attacks since December 2023 were first localized among shipping companies, ultimately, they will be felt by manufacturers and consumers around the world. Operation Prosperity Guardian—the U.S. Central Command task force organized to neutralize the Houthi threat to sea lanes—is a crucial test of whether the United States will continue to serve as the primary guarantor of global trade.
The Houthis first started attacking vessels in the Red Sea as far back as March 2015, utilizing a rudimentary network of sea mines and relatively aged anti-ship missiles captured from Yemeni government forces along with military, materiel, and technical assistance provided by Hezbollah and the Islamic Revolutionary Guard Corps. On the whole, these attacks were ineffective at stopping the flow of commerce; however, they successfully imposed costs on the Saudi-led coalition then fighting the Houthis, forcing them to devote resources to demining key waterways and directly countering Houthi attacks on shipping. By utilizing simple, inexpensive weapons to attack defenseless targets—i.e. commercial shipping—the Houthis discovered how to impose disproportionate costs on Saudi Arabia, their allies, and the wider Western world.
Despite deploying some of the most advanced air defense systems in the world, Saudi forces struggled to keep up with a drumbeat of Houthi missile and drone attacks since the conflict began in 2015. This was in part due to a lack of effective interceptors designed specifically to combat small, low-flying threats, but also to the mixed nature of Houthi attacks, which often employed a variety of threats simultaneously. The interceptors that did prove effective in combating Houthi attacks also turned out to be some of the most expensive, costing Saudi Arabia hundreds of millions of dollars in advanced munitions to mitigate low-level attacks by small drones and cruise missiles. This is gross overkill for weapon systems like the MIM-104 Patriot and AIM-120 AMRAAM, both of which were designed to intercept advanced aircraft and cruise and ballistic missiles of the type only a nation-state can afford to field. Expending these counter-munitions at a high rate to deal with low-level threats leaves a gap in air defenses which can then be exploited by more accurate, expensive, and advanced weapons. The evolving asymmetric war between air defense and inexpensive airborne munitions has also been seen in the ongoing war in Europe, where both Ukraine and Russia have struggled to economically intercept airborne threats.
Today, Operation Prosperity Guardian is the United States’ single longest naval engagement since the Second World War, supported by the extended deployment of some of the world’s most advanced warships. Though these ships are designed to project power and defend the United States and its allies from peer- or near-peer level threats, the Houthis are once again keeping a better equipped opponent on the back foot. Container shipping through the strait has dropped 90 percent since their attacks began in October 2023, with dozens of major maritime carriers sending ships the long way around the Cape of Good Hope instead of risking an attack, resulting in millions of dollars in additional costs for each vessel. The overall impact on global trade is substantial and rising. If Operation Prosperity Guardian is unable to restore free transit of the Bab el-Mandeb, the impact on American credibility will be substantial.
The ongoing Houthi attacks on commercial shipping occur at a time when advanced air defense resources are at a premium for the United States and its allies. Russia’s barrage of missiles and drones against Ukraine (oftentimes utilizing similar Iranian-designed munitions as the Houthis) and the threat of China in the Pacific has already placed strain on the inventory and availability of U.S.-made air defense munitions. The crisis in the Middle East post-October 7th, 2023 has seen the expenditure of even more advanced air defense munitions in an effort to protect Israel and ships passing through the Red Sea. So many missiles have been fired by the Navy against Houthi drones and missiles, that the Navy has requested hundreds of millions of dollars in additional funding to restock its missile inventory, further raising concerns about the relative cost disparity between advanced air defense missiles and the low-level airborne threats employed by the Houthis. While the exact cost of the individual weapons employed by the Houthis remains unknown, it is almost certainly a fraction of the cost of the weapon systems, vessels, and support staff required to intercept them as part of Operation Prosperity Guardian.
This stark disparity has ushered in a paradigm shift of strategic importance: either the United States finds a way to stop the threat here, or other groups will replicate the Houthis’ strategy elsewhere, undermining U.S. command of the seas. The success of Prosperity Guardian is of paramount importance to continued U.S. strategic dominance. While prior counterinsurgency operations against irregular forces in the Middle East proved vexing, the underlying assumption of American deterrence capabilities via superior financing and firepower was never seriously called into question by these campaigns. If a group with a fraction of the financial and material resources of the United States can wage a successful, sustained campaign of area denial against the United States, allies and adversaries alike will take note. American naval primacy—and therefore its superpower status—will be imperiled.
Cameron Keyani is the Director of Analysis at Artis International. He has a background in OFAC sanctions evasion investigations for federal law enforcement and in the private sector, and completed his Master’s thesis on IRGC Quds Force hybrid warfare in 2019.
Cameron Henley is an Analyst at Artis International. He holds a Masters of Law and Diplomacy from the Fletcher School at Tufts University, where his capstone research was focused on non-state actor used of unmanned aerial vehicles.
The views expressed in this piece are the sole opinions of the author and do not necessarily reflect those of the Center for Maritime Strategy or other institutions listed.