Michael O’Hanlon is a much-respected analyst of foreign policy, national defense, and military strategy at the Brookings Institution.[2] In Military History for the Modern Strategist: America’s Major Wars Since 1861, he looks back at the major wars fought by the United States since 1861. He devotes a chapter to each case study: the Civil War; the First World War; the Second World War; Korea and Vietnam (covered in a single chapter); and the past thirty-plus years of fighting by American forces in the Greater Middle East. A concluding chapter offers three big lessons based upon this study of the American experience with war. He explores what is commonly referred to as the American way of war.[3]
H-Diplo | Robert Jervis International Security Studies Forum
Review Essay 100
Michael O’Hanlon, Military History for the Modern Strategist: America’s Major Wars Since 1861. Washington, DC: Brookings Institution Press, 2023. ISBN: 978-08157-3983-8 (cloth, $39.95).
Reviewed by John H. Maurer, US Naval War College[1]
28 May 2024 | PDF: http://issforum.org/to/RE100 | Website: rjissf.org | Twitter: @HDiplo
Editor: Diane Labrosse | Commissioning Editor: Daniel R. Hart | Production Editor: Christopher Ball
Michael O’Hanlon is a much-respected analyst of foreign policy, national defense, and military strategy at the Brookings Institution.[2] In Military History for the Modern Strategist: America’s Major Wars Since 1861, he looks back at the major wars fought by the United States since 1861. He devotes a chapter to each case study: the Civil War; the First World War; the Second World War; Korea and Vietnam (covered in a single chapter); and the past thirty-plus years of fighting by American forces in the Greater Middle East. A concluding chapter offers three big lessons based upon this study of the American experience with war. He explores what is commonly referred to as the American way of war.[3]
O’Hanlon writes in a clear style, draws upon a wide range of published accounts to present solid narratives of America’s wars, and offers thought-provoking examinations of military strategy and operations. His goal is to draw insights from these case studies to inform current-day policy discussions about international challenges and strategic problems confronting the United States. The book is meant to be, as the title states, Military History for the Modern Strategist. O’Hanlon maintains that “[m]ilitary history is fundamentally sobering. For that reason its value is hard to exaggerate” (325). His case studies highlight high-level political and strategic decisionmaking in explaining the course and outcome of America’s wars.
In order to reveal history’s value for our own times, O’Hanlon shows a keen appreciation for the present in writing about the past. His chapter on the Civil War illustrates the importance of high-level leadership in wartime. The North’s victory depended upon President Abraham Lincoln finding a team of generals who were able field commanders, and were determined to push forward offensives to take the war to the South, defeat its armies, and overthrow the Confederate regime. In Ulysses S. Grant, Lincoln found a general to lead the war-winning drives of the North’s armies. Grant emerged as an indispensable army leader. O’Hanlon rightly notes that it took time to find and give command of the North’s armies to generals who were not overly cautious, who brought into play the North’s demographic and industrial strengths. The strategy to defeat the Confederacy demanded Union military leaders who were willing to take risks. “Looking back, we take Grant’s virtues of doggedness, persistence, and underlying confidence almost for granted,” O’Hanlon observes. He adds, “[b]ut they were perhaps at least as unusual a set of qualities as the earlier generals’ tendencies toward caution” (49).
In telling this tale of Lincoln and his generals, O’Hanlon is surefooted in his appraisals of generalship, noting that earlier commanders like George McClellan had valuable leadership qualities as well. He points out, “McClellan did have real strengths in terms of organization, logistics, and morale building among his soldiers, all traits that Lincoln appreciated” (49). McClellan built a powerful army that played a decisive role in defeating the Confederacy in the hands of Grant. As a field commander, McClellan lacked the leadership attributes of risk-taking and a bullish determination to fight through to victory.
Any examination of strategy in the Civil War, however, must acknowledge that the commander of the Army of the Potomac, the main Union army in the main theater of war, carried a unique command responsibility: he was the North’s only general who could lose the war in an afternoon.[4] The destruction of the Army of the Potomac in battle would have led to the fall of Washington, DC, the invasion of Maryland and Pennsylvania, and the collapse of morale in the North to prosecute the war. Given this responsibility and the stakes involved, little wonder, then, that before Grant’s arrival, the North’s generals in the eastern theater of war showed such risk-averse behavior.
Furthermore, in Confederate General Robert E. Lee, the Union generals in the east were up against a formidable foe. While grappling with Lee’s army, Grant’s offensive drive carried a high domestic political risk. Lee’s Army of Northern Virginia mounted a tenacious defense against Grant’s offensive. Grant’s overland campaign brought the Army of the Potomac to the outskirts of Richmond, but this offensive came at a frightful cost in casualties. These losses led Lincoln to fear quite rightly that he would lose the presidential election of 1864 to McClellan. What saved Lincoln politically from election defeat were the victories gained by the Union armed forces in secondary theaters: General William T. Sherman’s capture of Atlanta and march through Georgia to the sea; Admiral David Farragut’s victory in Mobile Bay; and General Philip Sheridan’s victories in the Shenandoah Valley campaign. These victories buoyed the North’s morale and carried Lincoln to victory in the presidential campaign.[5] Lincoln’s reelection ensured the South’s defeat.
Relating military risk to political risk stands out as an important topic in studying America’s wars. Assessment of risk is a paramount strategic question for political leaders and military commanders throughout history, whether the aim is to destroy the enemy’s forces or to preserve one’s own, whether to go on the offensive or stay on the defensive, and what level of casualties a society will tolerate before exhaustion and political opposition calls for an end to the fighting. Lincoln ran a great political risk in supporting Grant’s campaign that grounded down both his army and Lee’s. Lincoln’s willingness to accept heavy casualties demonstrates his determination to destroy the Confederate regime and preserve the Union. O’Hanlon underscores the high stakes involved in the Civil War, as leaders in both North and South defined the struggle “in existential terms. Each had a strong, even fervent commitment to its cause” (50). It is not surprising, then, that the war lasted for as long as it did and demanded “the last full measure of devotion” on the part of so many soldiers from North and South.
O’Hanlon’s account of the Second World War in the Pacific is especially insightful for understanding the difficulties and dangers that the United States would face in a future conflict with China. Japan’s strategic calculus in 1941 could well reflect the views of aggressive Chinese strategists today. O’Hanlon notes that
Japan’s leaders gambled that they could knock America out of the Pacific long enough to then consolidate a hold on key island chains throughout the broader region…. Seeing as much, Washington would view tactical defeat, and subsequent restraint, as a better part of valor, and concede the broader region to Japan (147).
The opening Japanese offensives did inflict defeats and heavy losses on American forces in the Pacific. Japan’s strike on Pearl Harbor damaged the American battle fleet, which President Frankin D. Roosevelt hoped would exercise a deterrent effect on Japanese decisionmakers. Instead, the deterrent became a target for Japan’s aircraft carriers to attack. The defeat at Pearl Harbor and subsequent Japanese victories did not break the American will to fight. The American people remained confident of victory despite these initial defeats. Still, during the six months after Pearl Harbor, Admiral Chester Nimitz, commander of the Pacific Fleet, was hard pressed to mount a successful defense, while preserving his forces and avoiding defeat (159).
The Pacific War also demonstrates the lethality of modern warfare at sea when the navies of great powers trade blows. Both Japan and the United States started the war with six large carriers. These carriers were the strike forces needed to spearhead offensive operations in the maritime environment. At the Battle of Midway, Japan lost four carriers in a single sea fight. Meanwhile, over the course of 1942, the United States Navy lost one carrier at the Battle of the Coral Sea, another at Midway, and two more in fighting during the Guadalcanal campaign. By the end of 1942, after a year of fighting, Japan and the United States had each lost four of the six carriers with which they entered the war. As O’Hanlon notes, it would take time before the balance of forces would shift decisively in favor of the United States (161-162). In June 1944, Admiral Raymond Spruance’s forces breached the island chain of Japanese defenses in the Battle of the Philippine Sea. The invasion of the Philippines and more victories soon followed in the autumn. With these defeats, Japan’s overseas empire in the Western Pacific was no longer tenable.[6]
Still, Japan’s military leaders remained convinced that they could mobilize the effort to prevent American military occupation of the Japanese homeland, the toppling of the imperial regime, war crimes trials, demilitarization, and the removal of the emperor. Japan’s leaders were no longer fighting for empire but to avoid a hostile American takeover to refashion Japanese politics and society. Inflicting heavy losses on American forces, so they believed, would lead the United States to relenting its harsh terms of unconditional surrender. American casualty lists in taking Iwo Jima and Okinawa did show that the fighting spirit of the Japanese armed forces remained high. These casualties also pushed American leaders to consider their strategy for defeating Japan.[7] President Harry S Truman, a veteran of the Meuse-Argonne offensive in the First World War, had witnessed firsthand the high casualties suffered by the American army in battling against an entrenched and determined enemy. He wanted to avoid a bloodbath like the one he had experienced. O’Hanlon notes that, to Truman and his strategic advisors, invading the Japanese “home islands augured far worse” casualties than those suffered so far by American armed forces (179). Only after careful consideration of the policy and strategy options was the decision made to employ nuclear weapons.
O’Hanlon wrestles with the question of whether alternative strategies existed for bringing about Japan’s defeat, and whether the harsh measures adopted by the United States in bombing Japanese cities was a strategic necessity for ending the war.[8] O’Hanlon admits to being “torn on the issue” (188). It is incredible that Japan’s military leaders remained committed to fighting even after the horrific firebombing of Tokyo, the nuclear attacks on Hiroshima and Nagasaki, and the Soviet entry into the war. Ending the war required that Japanese Emperor Hirohito step in to save his people further suffering (and, for that matter, his own skin) by agreeing to unconditional surrender and broadcasting his call for an end to the fighting. As is commonplace to say today, the enemy gets a vote. Hirohito “voted” to end the war, and the Japanese people breathed a collective sigh of relief, while Japan’s military leaders reluctantly followed their emperor’s command. Meanwhile, American leaders made the astute political judgment to keep the emperor on the throne and exploit his authority to legitimize the occupation of Japan. O’Hanlon finds it hard to defend the ferocity of the American aerial assault on Japan. Nonetheless, he recognizes that, “given the stakes entailed in this conflict, and the extreme depravity of America’s enemies, and the importance of ending these hugely deadly conflicts as quickly as possible, I find it difficult to object strenuously to tactics and methods that in most other wars could be construed as criminal” (189).
Today, Chinese military officers and strategic analysts seek to draw lessons from studying the fighting in the Pacific during the Second World War. Toshi Yoshihara analyzes Chinese strategic and operational histories of the campaigns in the Pacific War, and the attempt to apply this history to analyze a future conflict with the United States. Yoshihara examines Chinese writings on the campaigns of Midway, Guadalcanal, and Okinawa. These campaigns centered around contests for islands that involved aircraft carrier operations, land-based maritime strike, amphibious landings, and logistical support to project power over long distances.[9] Reading Yoshihara’s work alongside that of O’Hanlon is eye opening for considering competing strategies in a war between China and the United States. Both sides are pursuing strategies to offset the advantages of the other. In a future Sino-American clash, the lethality and wide range of weaponry that China and the United States can employ will result in losses on a scale that the American armed forces have not suffered since the Second World War. Moreover, both China and the United States today possess the ability to strike each other’s homeland with conventional, cyber, and nuclear weapons. Fighting in the Western Pacific might not be confined to the offshore islands of the region. While Japan began the fighting with attacks on American forward-deployed forces in the Pacific, the war ended with the use of nuclear weapons.
O’Hanlon’s narrative of the Korean War also serves up somber lessons that are also applicable for considering a future conflict with China. The Korean War started as a civil war when North Korea invaded the South to unify the country under Communist rule. American decisionmakers soon recognized that the South could not survive the North’s onslaught without the commitment of US armed forces. The US intervention in the fighting turned the tide and, after a masterful amphibious assault at Inchon, the North’s army was broken and in full retreat. Now the North stood in danger of complete defeat as the forces of the American-led coalition surged north toward the Chinese border. But the conflict escalated yet again when Chinese forces attacked into Korea. The Korean conflict had turned into a proxy war, with the Soviet Union supporting China and Korea in a contest against the United States. In the autumn of 1950, China’s opening strike against overextended, forward-deployed American forces inflicted a stunning defeat on the United States. To keep the war from escalating beyond the Korean peninsula, Washington imposed restrictions on targeting the Chinese mainland. These restrictions frustrated American military commanders, who viewed them as giving the strategic initiative over to the enemy. The famous civil-military clash between President Truman and General Douglas MacArthur revolved around disagreements about restrictions on the use of force as well as the strategic priority assigned to Korea in Washington’s overall strategy for the Cold War.[10] O’Hanlon rightly notes that MacArthur
saw the war in Korea as the chief focal point of the global struggle against communism and favored escalation not only to win the Korean war but to weaken the Chinese government more systematically. Truman along with his top advisers, including Secretary of Defense [George] Marshall and Secretary of State [Dean] Acheson, favored limiting America’s commitments and obligations in Korea and pursuing a peace process that more or less sought to restore the prewar boundary between the two Koreas (211).
MacArthur railed against Washington’s efforts to avoid unwanted escalation of the conflict. He labeled the administration’s policy appeasement, a sign of weakness that would fail to bring about a winning decision to the war. MacArthur’s outspoken public challenge of the president’s authority brought about the general’s firing. Truman, however, failed to end the fighting, and the battlefield stalemated along the 38th parallel. Only under Truman’s successor, President Dwight Eisenhower, was an armistice achieved. O’Hanlon argues that, under Eisenhower, “MacArthur wound up having more support for his proposed policy of escalation than many tend to remember. Like Eisenhower, the US Joint Chiefs were also supportive of the idea of using nuclear weapons if an armistice could not be secured” (213). The war ended in stalemate, after the loss of 34,000 American lives and over 100,000 wounded. Meanwhile, China suffered an estimated 900,000 killed and wounded (197). Today, China is much better armed than it was in the early 1950s, including nuclear weapons of intercontinental reach and an ability to challenge the United States Navy on the maritime commons. This change in the balance of forces will induce Washington to exercise even greater restraint in imposing targeting restrictions in any conflict with China.
In a concluding chapter, O’Hanlon presents the lessons that he has derived from studying the United States’ major wars. His first lesson is that outcomes in war are not preordained (315-317). One of the book’s strengths is O’Hanlon’s emphasis on the contingent nature of the outcome of America’s wars. The strategic choices made by political and military leaders mattered in deciding the course of these wars. He makes compelling arguments for how these wars could have had different outcomes. The second conclusion is that war is usually harder and bloodier than expected (317-321). America’s wars have been hard-fought struggles against determined adversaries. Even the campaigns fought against weak regimes and non-state actors in the Middle East over the past thirty-plus years have proved frustrating, with the region far from achieving a stable peace, as the recent upsurge in violence attests. Washington would like to pivot to Asia, but fighting in the Middle East keeps American armed forces engaged in the region. O’Hanlon’s third concluding take-away is that America’s grand strategy is strong enough to absorb setbacks (321-325). The United States has reservoirs of strength that other countries cannot match. The depth of power possessed by the United States has enabled it to keep fighting despite initial defeats in battle. The shock of Pearl Harbor did not break the will of the American armed forces, government, or people to fight. Nor did the Chinese victories over the winter of 1950–1951 push the United States to abandon South Korea to its fate. Even after humiliating defeats like those in Vietnam and Afghanistan, the United States has continued to play a leading role in Asia and the Middle East. O’Hanlon’s lessons amount to a call for realistic assessments and prudence in the making of American foreign policy and strategy. While O’Hanlon directs these lessons at an American audience, will China’s political and military leaders also find them compelling? History, however, cannot answer this question whether Beijing as well as Washington will take these lessons to heart.
John H. Maurer is the Alfred Thayer Mahan Professor of Sea Power and Grand Strategy at the Naval War College. He is the author or editor of books examining the outbreak of the First World War, military interventions in the developing world, naval rivalries, and arms control between the two world wars, and a study about Winston Churchill’s views on British foreign policy and grand strategy.
[1] The views expressed are those of the author alone, and do not represent the position of the United States government, Department of Defense, or Navy.
[2] His recent work includes Michael O’Hanlon, The Art of War in an Age of Peace: US Grand Strategy and Resolute Restraint (New Haven: Yale University Press, 2021); O’Hanlon, Defense 101: Understanding the Military of Today and Tomorrow (Ithaca: Cornell University Press, 2021); and O’Hanlon, The Senkaku Paradox: Risking Great Power War over Limited Stakes (Washington, DC: Brookings, 2019).
[3] The classic work in the field is Russell Weigley, The American Way of War: A History of United States Military Strategy and Policy (New York: Macmillan, 1973). A recent addition is Donald Stoker, Purpose and Power: US Grand Strategy from the Revolutionary Era to the Present (Cambridge: Cambridge University Press, 2024).
[4] I am paraphrasing, of course, Winston Churchill’s famous remark that Admiral Sir John Jellicoe, the commander of Britain’s Grand Fleet during the First World War, was “the only man on either side who could lose the war in an afternoon.” Winston S. Churchill, The World Crisis, 1916–1918 (London: Thornton Butterworth, 1927), Part 1, 112.
[5] James M. McPherson, Battle Cry of Freedom (New York: Oxford University Press, 1988); David E. Long, Jewel of Liberty: Abraham Lincoln’s Re-Election and the End of Slavery (New York: DaCapo, reprint 1997); John C. Waugh, Reelecting Lincoln: The Battle for the 1864 Presidency (New York: Crown Publishers, 1997).
[6] Paul Kennedy, Victory at Sea: Naval Power and the Transformation of the Global Order in World War II (New Haven: Yale University Press, 2022).
[7] Richard Frank, Downfall: The End of the Imperial Japanese Empire (New York: Random House, 1999).
[8] Robert James Maddox, Weapons for Victory: The Hiroshima Decision (Columbia: University of Missouri Press); Sadao Asada, “The Shock of the Atomic Bomb and Japan’s Decision to Surrender: A Reconsideration,” Pacific Historical Review 67: 4 (November, 1998): 477-512.
[9] Toshi Yoshihara, “Chinese Lessons From the Pacific War: Implications for PLA Warfighting,” Center for Strategic and Budgetary Assessment, 5 January 2023, https://csbaonline.org/research/publications/chinese-lessons-from-the-pacific-war-implications-for-pla-warfighting; Yoshihara, “Chinese Views of future Warfare in the Indo-Pacific: First Strike and US Forward Bases in Japan,” in John H. Maurer and Erik Goldstein, eds., The Road to Pearl Harbor: Great Power War in Asia and the Pacific (Annapolis: Naval Institute Press, 2022), 165-186.
[10] Allan R. Millett, The War for Korea, 1950–1951: They Came from the North (Lawrence, Kansas: University of Kansas Press, 2010).