Shortly after Russia invaded Ukraine in February 2022, acclaimed military historian Andrew Roberts contacted retired Gen. David Petraeus and proposed that the two write a book together that contextualized the conflict by considering the history of warfare from the mid-20th century to the present day.

Petraeus, who commanded U.S. forces in Iraq and Afghanistan among other high-level assignments during a 37-year military career, agreed to join Roberts on the project.

Their book, “Conflict: The Evolution of Warfare from 1945 to Ukraine,” describes the evolution of warfare over more than 75 years, drawing insights from a detailed analysis of the past, including Petraeus’ firsthand experiences as a commander in modern warzones.

Petraeus, who was appointed a Kissinger Senior Fellow at the Jackson School of Global Affairs in August 2023, recently discussed the importance of strategic leadership to modern warfare, the strategic mistakes made by U.S. leaders in Afghanistan and Vietnam, and how leadership has influenced the ongoing war in Ukraine. (The interview has been edited and condensed.)

In your book you emphasize the importance of strategic leadership in global conflicts since 1945. What makes a strong ‘strategic leader’?

David Petraeus: By “strategic leaders,” we mean the most senior civilian, which can be the president of the United States, the prime minister of the United Kingdom, and so forth, and then the senior military commander in the theater of war.

Strategic leadership has four tasks. The first and most important is to understand the nature of the conflict and get the big ideas right. You need to craft the right strategy, the right strategic approach. If you don’t get that right, everything that you do subsequently is building on a shaky intellectual foundation. The second task is to communicate these big ideas throughout the breadth and depth of the organizations or countries or coalitions that they lead, and, frankly, to all individuals who have a stake in the conflict.

The third is to oversee the implementation of the big ideas. This is what we think of as leadership. It’s energy, inspiration, determination, and fortitude. I called it “the battle rhythm” while applying this intellectual construct in the surge in Iraq first, then at U.S. Central Command, then in Afghanistan, and then as the director of the CIA. It includes making sure you’re using the right metrics to measure progress. Metrics must be rigorously developed and honestly tracked, unlike in Vietnam when the United States used body count as a primary metric, which became corrupted and undermined our integrity. You drive the implementation of the big ideas, in large measure, by meeting with various people, including subordinate commanders, and visiting the front to see things for yourself.

The fourth task, which is often overlooked, is to determine how to refine the big ideas to the reality on the ground and repeat the process of communication and implementation as needed.

What are some examples where the quality of strategic leadership on one side or another proved decisive?

Petraeus: In the conflicts we studied, the side that had benefited from strong strategic leadership usually prevailed. In the Vietnam War, for example, the most effective strategic leader was Võ Nguyên Giáp, the North Vietnamese battlefield commander who defeated the French at Ðiện Biên Phủ and then served in higher level positions during the war with the United States. The French in Algeria suffered from poor strategic leadership as did the Nationalists during the Chinese Civil War.

By contrast, the Sultan of Oman and his British partners demonstrated impressive strategic leadership during the Dhofar War in defeating a formidable Marxist guerrilla movement. In the Malayan Emergency, Gerald Templer, Britain’s high commissioner for Malaya, proved to be a strong strategic leader in defeating the Malayan National Liberation Army. The United States benefitted from strong strategic leadership in Operation Desert Shield and Operation Desert Storm, the two phases of the Gulf War.

In Iraq and Afghanistan, impressive initial campaigns to topple regimes were followed by not-so-impressive post-conflict planning and execution [by U.S. leaders]. Although I’d contend that we sorted it out for a period in Iraq. Then things went downhill again. Then we conducted the surge, which drove violence down by nearly 90% and gave Iraq an entirely new opportunity. We kept the violence down for another three and a half years until our combat forces withdrew.

You write a chapter on the Vietnam War. What was it like to revisit the conflict, which was the subject of your doctoral dissertation at Princeton?

Petraeus: I hadn’t deeply examined the literature on Vietnam since I wrote my dissertation about 10 years after the collapse of South Vietnam in 1975. It was revelatory in several different ways.

For example, I realized even more than I had before how inadequate the strategic leadership had been in the theater. Right at the beginning, in the mid-1950s, the South Vietnamese rightly believed that they needed forces for a counterinsurgency. Their concerns had to do with guerrillas and what would become the Vietcong in the villages and hamlets. The United States, relying on the lessons of the Korean War, disputed this, arguing that they needed divisions. We aimed to help them build divisions that looked just like our divisions, because our leaders believed the biggest threat was the North Vietnamese invading across the newly established demilitarized zone that partitioned Vietnam into North and South after the French withdrawal.

This flawed approach continued until 1968, when General Creighton Abrams took over as commander in the theater and got the big ideas right, by and large, and improved the organizational architecture and overall strategy. But by that point, domestic political opinion had turned so heavily against the war that it really wasn’t possible to completely turn it around. Although they did an impressive job of trying.

The context of Vietnam was just so challenging that we could’ve gotten everything right and still failed to meet our objectives. We had to contend with the frailty of our partners, particularly senior South Vietnamese leaders, who were quite disconnected from the people in the countryside, the ability of the North Vietnamese to use sanctuaries in other countries to enter the South, and the support they received to varying degrees from the Soviet Union and China, and a variety of other challenges. It could be that success there was just beyond our reach.

The chapters on recent U.S. wars in Iraq and Afghanistan were based partly on your firsthand experience as a commander in both conflicts. The latter, which would become the country’s longest war, ultimately resulted in the Taliban’s return to power. What did the United States initially get wrong there?

Petraeus: I contend that it took us nine years in Afghanistan just to get the inputs right after a very impressive campaign to topple the Taliban regime after they refused to turn over Al-Qaeda’s leadership to us. We also eliminated an Al-Qaeda sanctuary, although Osama bin Laden escaped. Of course, we got him some 10 years later, when I was privileged to be the commander, and a combined operation of our special mission unit and the CIA tracked him down and brought him to justice. But in that conflict, after that very impressive initial campaign, we really did not craft the right strategy, didn’t land on the right big ideas, and didn’t have the right level of resources deployed.

Success there required a comprehensive civil-military counterinsurgency campaign within which our counter-terrorist forces carried out precision operations. We also didn’t achieve the right personnel levels until late 2010. Not just of our forces and other forces, but also diplomats, spies, development workers, anti-corruption experts, and so on.

And then, unfortunately, we only kept the big inputs right for about six or seven months before we started a drawdown. I’d identified these shortcomings in an earlier essay published in The Atlantic, and then expanded on them considerably in the chapter on Afghanistan.

How has strategic leadership affected the current war in Ukraine?

Petraeus: The situation in Ukraine is very interesting for a variety of reasons, one of which is the quality of the strategic leadership on one side and the deficiency of it on the other. President [Volodymyr] Zelensky has been a superb strategic leader. Remember his first big idea was to say that he needed ammunition, not a ride. He stayed in Kyiv with his family. He mobilized the entire country. Russia still has not done that.

Zelensky’s communication skills have been Churchillian in the way he addressed the British Parliament, the German Bundestag, and the U.S. Congress. He’s provided the energy and inspiration of a good strategic leader. And his military leadership has been equally impressive. The Ukrainians won the battles for Kyiv when Russia’s goal was to take the capital city, topple the government, replace President Zelensky with a pro-Russian figure, and then essentially go home to a victory parade. Obviously, that was a very flawed big idea. But they also lost the battles of Sumy and Chernihiv, two other northeastern cities. They failed to take Kharkiv in the east, Ukraine’s second-largest city. In the southwest, they crossed the Dnipro River, but got nowhere near Odessa, which was their objective.

They were forced to withdraw the forces west of the Dnipro River, which bisects Ukraine roughly from north to south. But then the lines have hardened, and the hoped for offensive gains of the Ukrainians did not materialize this summer for a variety of different reasons, the most significant being the depth of the Russian defenses, which feature minefields that are miles deep augmented by trenches, barbed wire, and drones.

In our doctrine, we require air superiority to conduct the kind of armored breaching such an offensive requires. The Ukrainians don’t even have air parity. The United States made the decisions on supplying tanks, which delayed the German decision to allow its Leopard tanks to be provided to Ukraine. Our M1 Abrams tanks only recently reached Ukraine. We didn’t provide large numbers of armored breaching systems and didn’t get the F-16 fighters to them in time for the summer offensive, which might have made a difference.

This story originally appeared in Yale News