Andrew Walter Marshall, a former strategist at the RAND Corporation who served as head of the Pentagon’s Office of Net Assessment from its founding in 1973 until his retirement in 2015, died last month at the age of 97. Despite his aversion to publicity and the innocuous title of the office he led, Marshall stands among the most consistent and perceptive contributors to U.S. national security and defense strategy since the United States emerged as a global power nearly 80 years ago. Marshall’s innovative work on how to plan for long, open-ended conflicts was, like its creator, a product of the Cold War, but its value persists. Today’s Pentagon no longer has to keep pace with Soviet Russia, but Marshall’s insights into the fundamental drivers and measures of military power will continue to serve Washington well as it enters a new age of high-tech warfare and confronts rising revisionist powers such as China.

During his decades-long tenure at the Pentagon, Marshall became known in defense circles as Yoda, after the Star Wars character famous for his short, cryptic comments and his special understanding of the Force, a kind of metaphysical power. Although Marshall was no fan of the comparison, it had some merit. He was indeed a man of very few words. And he was best known for developing a strategic planning methodology—net assessment—that was so difficult to grasp that many simply defined it as “what Andy Marshall does.”

Marshall’s career began at the RAND Corporation in the late 1940s, a time when intellectual titans such as the Cold War theorists Herman Kahn and Albert Wohlstetter were walking the think tank’s halls and wrestling with the conundrums of the infant nuclear age. Even in this august group, one colleague described Marshall as “first among equals.” At RAND, Marshall questioned the assumption, common at the time, that states made decisions just like a rational, value-maximizing individual would. Working with his colleague Joseph Loftus, he argued that governments were so large and complex that no single central authority had enough time or information to make optimal decisions. States did not choose the most effective solutions; they usually chose ones that were simply good enough. This dynamic could be exploited: Soviet bomber bases, Marshall and Loftus discovered, were far more vulnerable to U.S. surprise attack than they would be if positioned optimally.

Marshall questioned the assumption, once commonplace, that states made decisions just like a rational, value-maximizing individual would.

Marshall brought these insights to the May Group, a research collective formed in the 1960s with Harvard Professor Ernest May, his colleague Richard Neustadt, a small group of other distinguished colleagues, and a young student rapporteur, Graham Allison. In 1971, Allison, by then a Harvard professor himself, published a pathbreaking analysis of Soviet and U.S. decision-making during the Cuban Missile Crisis. Allison credited Marshall as the source of his insights on the role organizations played in the crisis. Allison also cited the military historian Roberta Wohlstetter’s seminal work, Pearl Harbor: Warning and Decision—which was inspired by none other than Marshall. Mentoring others became one of Marshall’s most satisfying endeavors. Over time, many of his acolytes (graduates of “St. Andrew’s Prep,” as they called themselves) went on to high-levels positions in academia, diplomacy, and the military.

In his own work, Marshall increasingly turned his attention to the military balance of power. His aim was to find a better measure of military capability than more quantitative methods such as systems analysis tended to yield. Progress was slow. But by the early 1970s, Marshall, then a member of Henry Kissinger’s National Security Council staff, had developed the intellectual foundation for net assessments. Instead of merely counting troops, warheads, and the like, Marshall advocated a more comprehensive approach, factoring in everything from weapons systems to operational doctrines, logistics, and training regimes.

Marshall scrupulously avoided setting down any rigid guidelines for net assessments, making his a living methodology that has been refined over time. The assessments did, however, have defining characteristics. They were holistic, taking into account factors such as demographics, domestic unrest, and organizational culture. Above all, they did not avoid uncertainty; they embraced it. Marshall rejected any notion that the outcome of a war could be predicted in advance. But he hoped to reduce uncertainty where possible while searching for sources of U.S. advantage and rival weakness that could be exploited.

To the frustration of some, Marshall’s assessments were diagnostic in their focus and rarely prescriptive. “I’d rather have decent answers to the right questions than great answers to irrelevant questions,” he told his staffers. In his mind, analysts had to be careful not to press for actionable instructions too quickly, lest this bias for action corrupt objective analysis and wind up undermining the entire undertaking. The key was to get an accurate diagnosis. Without it, the defense strategy and program—the prescription—might end up focusing on the wrong problem.

Most net assessments fit into one of two categories. Regional assessments, such as a comparison of NATO and Warsaw Pact forces in Central Europe, took stock of the military balance in various geographic hotspots. Functional assessments focused on a particular aspect of the competition, such as the U.S.-Soviet nuclear balance. In one of his most influential projects, Marshall assessed the relative burden that the United States’ and Russia’s military investments were imposing on their respective economies. Whose side was time on?

In the mid-1970s, the Soviet Union appeared, on the surface, to be gaining the upper hand. Moscow no longer just had superior conventional forces; it had also reached a rough nuclear parity with Washington. Perhaps most sobering were CIA reports that the Russians were not only outpacing U.S. military production by a wide margin but doing so at much lower cost. Taken at face value, these estimates suggested that Russia was far more efficient at generating military power. If this were so, then the military balance would likely continue shifting in the Soviets’ favor.

Marshall challenged the CIA’s narrative, eventually persuading the intelligence community that the cost of the Soviet military buildup was substantially higher and Russia’s economy significantly smaller than generally believed. In May 1976, the CIA abruptly and dramatically raised its estimate of the Soviet Union’s military burden from six percent to between 11 and 13 percent of GNP. The point was made. The United States wasn’t falling behind. If anything, time was on its side. Fifteen years later, history proved Marshall right.

Anonymity outside the halls of the Pentagon never bothered Marshall, as he always had access to what he considered to be his primary audience: senior defense policy-makers.

Rather than simply emphasizing threats, Marshall sought to identify and exploit Soviet weaknesses. The United States, he argued, should pursue strategies that imposed disproportionate costs on the Russians. The concept was simple yet profound. After the Carter administration canceled the B-1 bomber program in 1977, Marshall urged defense secretary Harold Brown to “stay in the bomber business.” American nuclear missiles could strike the Soviets far more effectively than bombers, Marshall conceded, but U.S. policymakers needed to look at the bigger picture: Soviet Russia had the world’s longest border and a repressive regime determined to control access to its territory. To this end, it had deployed an enormous air defense system, primarily to defend against American aircraft. Maintaining the U.S. bomber fleet would motivate the Soviets to keep investing in their air defense system, which was far costlier than the U.S. bombers. The Russians would be left with less money to invest in offensive capabilities, such as tank armies. Marshall also noted that the B-2 stealth bomber, which the United States was developing at the time, would eventually make much of the Soviet air defense system obsolete. By the mid-1980s, such cost-imposing “competitive strategies,” as Marshall called them, had become a centerpiece of U.S. defense strategy.

Anonymity outside the halls of the Pentagon never bothered Marshall, as he always had access to what he considered to be his primary audience: senior defense policy-makers. Although he was a political appointee in a city that too often values self-promoters over people of substance, Marshall was invited to stay on by Democratic and Republican administrations alike—a testament to the respect he commanded within the national security world. Twice, however, his office was at risk of being marginalized by administrations that had yet to appreciate the value of his work. Both times, senior members of Congress raised their eyebrows, and plans to restructure the office were quickly scuppered.

As the Cold War neared its end, Marshall already had his eye on distant horizons. As early as 1987, he argued that that a rising China would be a more significant rival in the decades to come than Soviet Russia. He was equally prescient in forecasting a new era of precision warfare, a prediction confirmed in the Gulf War four years later.

Marshall’s greatest legacy—net assessment—grew out of the Cold War, but it has withstood the test of time. U.S. defense policymakers will always want to know how the United States stands in the military balance with rival powers, how to measure the trends that can shift that balance, and how these trends can be influenced. The first post–Cold War net assessment, published in 1992, triggered a debate on the “revolution in military affairs”—the way that new technologies were transforming the character of warfare. It also anticipated the threats that would arise if potential rivals, such as China, managed to use these technologies to block U.S. access to airspace and sea lanes—a major challenge for the U.S. military in the Indo-Pacific today.

What should a net assessment of the current U.S.-Chinese rivalry look like? It should no doubt begin by exploring China’s geopolitical objectives and its portfolio of current and potential future allies, asking how these might challenge core U.S. security interests. Next, the assessment might turn to today’s military balance in key geographic regions and different settings (think undersea warfare). The size of each side’s armed forces, their makeup (volunteers or conscripts?), the type and quality of their equipment, as well as their training and military doctrines will all come to bear on this analysis. Scenario-based planning will help identify key asymmetries between the two sides, so that U.S. advantages can be exploited and weaknesses mitigated.

Net assessment grew out of the Cold War, but it has withstood the test of time.

Current competition with China has no predictable endpoint. Any net assessment will therefore have to grapple with the factors that might shift the military balance in the decades ahead. This means that demographics, domestic social stability, environmental degradation, and long-term economic growth matter just as much as more obvious developments in arms production and dual-use technologies. 

Perhaps the enduring value of Marshall’s work is best judged by its principal customers. When the Obama administration considered shutting down the office in 2013, six former defense secretaries signed a letter opposing the plan. The letter offers a fitting epitaph. Marshall’s office, it declares, has “repeatedly paid enormous dividends during some of the most challenging periods in our recent history. We are now entering another such period, one in which the contributions of the Office of Net Assessment will be needed every bit as much as they have in the past.”

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