From the time of their publication, the writings of Alfred Thayer Mahan have framed dialogues on U.S. sea power, sea control, and maritime strategy. However, in the combined 840 pages of The Influence of Sea Power Upon History:1660–1783 and The Interest of America in Sea Power, Present and Future, Mahan does not investigate the role of a nation’s coast guard.
Today, as nations increasingly deploy their coast guards to assert sovereignty, the role of coast guards within Mahan’s conceptions of maritime power—namely, to maintain a nation’s access to the global commons and thereby bolster its domestic shipping capability—warrants further examination. As the United States refocuses on great power competition and reevaluates its maritime strategy, it must consider the critical duties of the U.S. Coast Guard, even if Mahan did not.
Mahan’s Surprising Omission
Mahan intended for his writing to educate the American populace on the strategic value of sea power and to advocate for expansion of the U.S. Navy.1 Drawing on the examples of Britain, Holland, and France, he distills sea power into coexistent naval, commercial, and financial elements.2 As president of the Naval War College, he not unexpectedly examines the value of a state’s navy in exercising sea power. Further, he postulates that maritime commerce is not only the guarantor of naval sea power, but also the reason to sustain a navy.3
Surprisingly, Mahan omits the role of the U.S. Revenue Cutter Service in preserving the commercial and financial elements of sea power.4 Perhaps he neglected the service because he felt it fell under the umbrella of the greater naval service or that its inclusion diverted attention from his larger focus on the U.S. imperative for “blue water” naval projection.
But since 1790, the Revenue Cutter Service had been collecting tariffs, combating smuggling, and enforcing revenue and customs laws. Apart from temporary wartime diversions, it persisted largely in that capacity until the end of the 19th century.5 These duties fell squarely within Mahan’s principles of maintaining open ports, preventing blockade, and protecting commercial maritime interests.
The Coast Guard’s Sea Power Contribution
In the decades following Mahan’s death, Coast Guard authority expanded to encompass all aspects of domestic sea power, with responsibility for the totality of the nation’s marine transportation system, including the free flow of commerce through the nation’s ports.
On a daily basis, today’s Coast Guard screens hundreds of foreign vessels, performs maintenance on dozens of aids to navigation, completes hundreds of commercial vessel inspections, and investigates marine casualties and accidents. In addition to icebreaking in northern ports, its collective activities ensure the integrity and continued viability of U.S. maritime trade.
Consider the March 2021 grounding of the M/V Ever Given in the Suez Canal. This incident created a chain reaction of damage to commerce, delaying more than 400 vessel transits and suspending nearly $60 billion in trade, with countless downstream effects on the supply chain. As the custodian of U.S. ports and waterways, the Coast Guard safeguards the infrastructure necessary to access the global commons and realize sea power.
Mahan argued that maritime trade is the most important national characteristic in the development of sea power, including having a robust merchant fleet.6 At the time of his writing, this was true for the United States. Today, however, the U.S.-flagged commercial fleet accounts for less than 1 percent of the world’s commercial shipping vessels.7 Critical to mitigating this deficit is the Coast Guard’s port state control program, which inspects “foreign ships in national ports to verify that the condition of the ship and its equipment comply with the requirements of international regulations and that the ship is manned and operated in compliance with these rules.”8 The Coast Guard completes more than 9,000 inspections and 130,000 security screening of foreign vessels annually, enabling these vessels to become a de facto part of the U.S. trade fleet.
Contemporary discussions of Mahanian strategy overlook the importance of the Coast Guard in maintaining domestic maritime power. Indeed, many contemporary maritime strategists regard the Coast Guard as a white-hulled extension of the Navy rather than the linchpin in preserving U.S. maritime trade.9
But as Mahan noted, naval power constitutes only a portion of a state’s sea power. Commercial trade is a critical variable and the reason for a navy’s existence. While Mahan could work under the assumption of robust U.S. commercial shipping, modern strategists do not have the same luxury. The United States must protect its domestic shipping infrastructure to access maritime trade, and the Coast Guard is the agency bearing the responsibility.
Before shifting the Coast Guard’s focus to the Indo-Pacific and beyond, the United States must ensure its own commercial maritime viability. Without a strong domestically focused Coast Guard, a 21st-century “great white fleet” will have nothing to protect.
1. Nicholas Lambert, “What Is a Navy For?” U.S. Naval Institute Proceedings 147, no. 4 (April 2021).
2. Jon Tetsuro Sumida, “New Insights from Old Books: The Case of Alfred Thayer Mahan,” Naval War College Review 54, no. 3 (Summer 2001): 100–101.
3. Alfred Thayer Mahan, The Influence of Seapower Upon History: 1660–1783 (Boston: Little, Brown and Company, 1890), 26.
4. Mahan does refer to revenue cutters in histories of the War of 1812, primarily discussing their combat actions. Alfred Thayer Mahan, Sea Power in Its Relations to the War of 1812, vol. II (London: Sampson Low, Marston and Company, 1905), 164.
5. U.S. Coast Guard’s Historian’s Office, “The 1700s–1800s,” www.history.uscg.mil/Complete-Time-Line/Time-Line-1700-1800/.
6. Mahan, The Influence of Sea Power, 53.
7. Jeremy Greenwood and Emily Miletello, “To Expand the Navy Isn’t Enough. We Need a Bigger Commercial Fleet,” Brookings, 4 November 2021.
8. International Maritime Organization, “Port State Control,” www.imo.org/en/OurWork/IIIS/Pages/Port%20State%20Control.aspx.
9. B. A. Friedman, “Command of the Littorals—Insights from Mahan,” The Strategy Bridge, 10 October 2017; and David Ramassinii, “Too Small to Answer the Call,” U.S. Naval Institute Proceedings 143, no. 5 (May 2017): 28.
