Michael O’Hanlon on the Myth of American Isolationism, “Thinking Long-Term” in Defense Strategy, and How to Protect Time for Real Research

Michael O’Hanlon has spent his career asking a deceptively simple question: how should the United States design its military—its budgets, posture, and strategy—for the world it’s actually in, not the one it wishes existed. In our conversation, he traces that “through line” back to a winding start: a physics degree, a Peace Corps stint, a near washout in graduate school, and then a catalytic insight in 1987—when he began imagining what U.S. defense policy might look like after the Cold War.
We also talk about the research habits behind long-form work: how he chooses questions, how a “working hypothesis” evolves as the evidence piles up, and how he decides when a project is done. Along the way, he shares a core argument from his newest book—that “isolationism” is a poor descriptor of American history—and closes with practical advice for students trying to build the concentration and discipline that serious thinking requires.
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-Michael O’Hanlon is the Philip H. Knight Chair in Defense and Strategy and director of research in the Foreign Policy program at the Brookings Institution, and author of To Dare Mighty Things: U.S. Defense Strategy Since the Revolution (released January 13, 2026).

Career through-line: from physics to strategy
Benjamin Wolf: Dr. O'Hanlon, thank you for joining me. For readers who may be unfamiliar with your career path—your through line—if you had to describe your work in a few sentences, or the main question you’ve been trying to solve throughout your career, what would it be?

Michael E. O’Hanlon: Thanks, Ben. Nice to be with you. I got into the field in the 1980s. I was born in ’61. I went to college; I studied physics. I graduated from Princeton with a physics degree in 1982, but I’d always had an interest in history as well. That was my favorite high school course—AP American History.
I also really enjoyed the January term at Hamilton College, where you had a 3.5-week compressed focus on one subject—one course—and I always did history in that. I’m telling you this because I figured out I really needed to get intense about physics. I transferred from Hamilton to Princeton—Hamilton was good, but small—and I sort of ran out of physics courses.
I still have mixed feelings about leaving Hamilton. I have fond memories, and I still teach once a semester at Colgate, which is really next door in central New York.

Leaving physics—but not science
​MO: At any event: I went off and did the Peace Corps. I needed a break from college. I always knew I wanted to do grad school—there wasn’t really any doubt—but I was a little burned out and a little unsure what to do next. I had this great interest in physics, but I almost mimicked the graduate school experience already in my last two years of undergrad, because the Princeton Physics Department was so good.
We had a lot of interaction with graduate students and fantastic professors, and I was way into it—taking two or three physics and math courses every semester. So I maybe overdid it a little bit.
And I was also unsure. At Princeton, I saw that while I was good at physics, I wasn’t the best. It didn’t cause a crisis of confidence overall, but it made me think: it’s not like I’m God’s gift to physics. It’s not like I have to go out and figure out what’s happening in some nebula someplace because I’ve been empowered with these physics neurons. In a way, I felt liberated not to be the best.
So I went off to the Peace Corps, taught physics, did some additional projects while there. And then I went to graduate school, still unsure what I wanted to do, but I applied to programs in science and public policy. That’s sort of all I knew: I wanted to combine those. I didn’t know how. I didn’t really know what that meant. I didn’t even know what courses that would entail.

Graduate school struggles and a turning point
I did those applications while sitting in my little house in the middle of Congo—way before the internet, when phone service was terrible. My only way of learning about different colleges in the U.S. was through the diplomatic pouch of the State Department and the mail. So I sent for brochures, and at that point—being far away from home—I had a proclivity to want to go back to something familiar. I was a little homesick.
So I went back to Princeton, knowing I was going to change department anyway. I wasn’t going to be in physics. Still not sure what it really meant to do science and policy together. I’m still pretty young at this point—only 23. I come back from the Peace Corps, launch into this program.
I found a group doing arms-control-related research that I really liked—and I liked the people—but the coursework was primarily within the engineering school. That’s where they directed me with this program in science and policy. I was doing just fine with the engineering, but I wasn’t really clear on how to combine that with my interests in policy. And frankly, I struggled.
To only slightly exaggerate—and not bore you with too much of the story—I basically almost failed out of grad school twice. I would have failed out with a master’s degree, so it wouldn’t have been the end of the world. It would have essentially been concluded between me and the faculty that there wasn’t a good Ph.D. path for me, and that I should take the master’s degree and run with it.
That would not have been so bad. But luckily, I kept at it. I had some professors who really helped—took a personal interest in me—and helped me get through these setbacks. By 1987—now I’m three-plus years into grad school—I finally got through the general exam process. By this point I had switched over: not in the engineering school anymore, but to the public policy school—what was then called the Woodrow Wilson School of Public and International Affairs at Princeton.

Imagining the post–Cold War world
MO: Anyway: by 1987, Ronald Reagan and Mikhail Gorbachev were starting to get along better. The U.S.-Soviet relationship was improving, and it looked like we might actually see an end to the Cold War. Just to remind folks: the Berlin Wall fell in November 1989—November 9, 1989. So here I am in the summer/fall of 1987.
I see the improvement, and I think I see where it’s headed. But most of Washington and the policymaking elite could not yet conclude there would be any near-term end to the Cold War. There was no way to foresee when it would happen.
So people at places like RAND—and even Brookings—were not yet doing studies on how you might envision a post–Cold War foreign policy, or specifically, in my case, a post–Cold War U.S. defense policy.
So I decided to make that my dissertation. And it was the benefit of being in an academic setting at a policy school, where you were trying to do policy-relevant research—but you had a little more freedom to think long-term than people inside the Beltway.

From dissertation to lifelong research agenda
MO: That was the key insight—the key decision—when I decided to do my dissertation on how to imagine rebuilding a U.S. military and global force posture for a post–Cold War world.
I was off to the races. Ever since then—whatever people think of my work—I’ve been on a consistent path. I haven’t had big doubts about what I was doing or whether I was properly trained for it.
I spent five years on Capitol Hill at the Congressional Budget Office from 1989 to 1994—that’s when the Berlin Wall fell, when the Soviet Union dissolved, and when Operation Desert Storm was conducted to expel Iraqi forces from Kuwait. A lot was going on. That was a fun time to be on Capitol Hill, but I’ve been at Brookings—on payroll—ever since 1994.
In that period I’ve had the opportunity to learn about a lot more things, to continue my education through research—sort of think of my job as both at the same time. More recently, I’ve done these books on military and defense history, which in many ways are the books I wanted to read when I was back in graduate school.
So the key turning point was 1987—the decision to pursue that dissertation—after struggling through the academic precursors and hurdles. But from roughly ’82 to ’87—ages 21 to 26—I was searching and unsure.

How he researches: choosing questions and testing ideas
BW: You conduct research for Brookings, but with writing your own book, that is, of course, too, a glacial amount of research. What’s your process? Where do you look first? How do you test that it’s going to be a good question to write about—and how do you know when the work is finished?

MO: It’s an excellent question—maybe the most important of all when you’re in this kind of field.
Generally speaking, I’m always kicking around a few ideas in the back of my head—when I’m driving somewhere, or on a long jog—things I might be interested in working on. They’re often topics in the policy debate today, or things I think I should know better than I do.
For example, the book I just published--To Dare Mighty Things—came out this week: a history of U.S. defense strategy ever since the American Revolution. That’s a book where I had curiosity about the subject for a long time. I broached it wanting to learn better—figuring that if I, at this point in my career, still didn’t feel like I had a good understanding of that topic, a lot of other people probably didn’t either, and maybe the book would be useful to them.
My hope was also that I might identify some patterns—some tendencies—in American decision-making, military policy, strategic culture—call it what you will—that we’d be well-advised to understand about ourselves. Because you don’t want to operate on the world stage naïve about who you are as a country and a people, and about how other countries see you. But I think we often are a bit naïve.
That was the motivation. I wanted to do these last two books—about military history and military strategy—for decades. What I really wanted was to read them more than to write them. But writing became almost a double pleasure: it meant I could immerse myself longer and get paid to do it, since that’s what my job allows—as long as the books are relevant and I stay engaged in the near-term policy debate while doing longer-term projects.
So curiosity has to be the number one answer—but curiosity not in some abstract intellectual sense, because I’m not a pure academic, and I’m not a plasma physics researcher studying the Big Bang. I’m doing think tank work a mile from the White House, a mile and a half from Foggy Bottom, four miles from the Pentagon, two miles from Capitol Hill. There’s a reason Brookings is where it is and why I live where I do.
So the curiosity is always in pursuit of a better understanding of American foreign policymaking—with a goal of contributing to future policymaking.
A couple more thoughts. I usually begin not just with an interest in a subject, but with a little bit of a working hypothesis about what I might want to argue. It’s a fine line: you want to stay open-minded about changing your argument as you learn more, and as you do analysis that improves your understanding.
A lot of times, you have to modify the argument as you go. Hopefully I don’t wind up completely turning it upside down—although it’s okay if that happens, because that’s the whole point of research: to understand things people didn’t previously understand. And you might conclude you were wrong—that the answer is 180 degrees from what you expected. That’s okay.
But usually I modify more like 30 or 45 degrees—not 180. I don’t completely change direction. I often come up with a more focused, specific, sometimes more nuanced thesis.
And I like working on subjects where I have some knowledge going in—pretty good knowledge—but also where I’m curious to understand better. If I didn’t know anything about the topic, it probably would not be a good thing to ask Brookings to pay me a couple hundred thousand bucks a year to work on—it would be like going to school, freshman year, and getting paid for it.
So I should work on things where I’m already reasonably conversant with the material. But if I already thought I had the whole thing figured out, I’d probably just write newspaper op-eds and journal articles and push out my message—and wouldn’t need the time and effort of a book research project.
So I’m usually looking for something in the middle: where I’m already knowledgeable, and where I want to learn a lot more.

What history shows: the “restless” United States, then and now
BW: Let me ask more about your new book. You look at U.S. defense strategy since the American Revolution. Were there any trends you found especially fascinating—and does it tell you anything about defense policy today, whether in Latin America, the Middle East, or the Arctic?

MO: Yeah, for sure. The overall argument that I make is that the United States has always been energetic, entrepreneurial, restless, and assertive in foreign policy and military policy.
You’re a lot younger than I am, so you’re closer to high school. I don’t know how American history was taught to you, but my memory is that a large fraction of the literature was people saying: we came to America to get away from all the silly wars in Europe and all the kings and monarchs. We wanted to build a democracy here. We wanted to be left alone. We fought off British oppression, and then we really just wanted to build our own country—and we only got involved in foreign policy when we had to, because in the early twentieth century Europe kept getting involved in big world wars, and Asian powers too, and they needed our help.
And I’ve come to believe that’s not true. That narrative is bunk.
We were never content to be a peaceful, isolationist country. It’s obvious when you think about it: a country that began as a swath of land along the eastern seaboard and then grew to be a continental power from the Atlantic to the Pacific did not do that by just being peaceful. We took land from other people.
Now, yes—we bought the Louisiana Purchase from France, and we bought Alaska from Russia—but even Louisiana Purchase territory needed to be, in our estimation and our ancestors’ estimation, conquered, because there were other people living there at the time. We didn’t develop some Machiavellian master strategy, but we did it incrementally. We pushed Native Americans west, eventually pushed them onto reservations. We always thought we were making a deal where we’d share the land—and then we got hungry for more land.
I don’t write a revisionist history in the sense of an anti-American tirade. If we hadn’t done these things—if we hadn’t taken the Southwest from Mexico in the U.S.-Mexico War of 1846 to 1848—we wouldn’t be this great continental world power that could have helped save the world in World War I and World War II and keep the peace in the Cold War.
So I have mixed views from an ethical perspective on the nineteenth century, but there’s no doubt we were super assertive. The last thing you’d call us, by any fair measure, is isolationist—or peaceful.
I think Americans are a very good people. I think we’ve done a lot of good in the world. But I don’t think we’re peaceful. I think we’re restless—verging on hyperactive—and sometimes looking for a fight. Sometimes not using military force as a last resort.
And in this sense—sort of obvious where I’m going—in this sense, while I’m not a supporter of Donald Trump, and I think he’s a different kind of president than everybody since 1945 (or since 1932 when Roosevelt was elected), I think his restlessness is not uncommon. It’s not unique.
Now: to see it apply to Greenland and ideas like that—that’s bonkers. I think it would be terrible for the world and for our long-term interests if President Trump were really to use military force to take Greenland. In fact, I think he’s already going way too far even to threaten military operations to do so.
But the energy associated with him is, in many ways, typical of our history.
The presidents whose policies, in some cases, foreshadowed what Trump would do—or where you hear echoes—my short list: President Madison with the War of 1812 (a war we probably shouldn’t have fought); President Monroe and the Monroe Doctrine of 1823, claiming more or less U.S. jurisdiction over the entire Western Hemisphere at a time we had basically no navy—so it was a bit of chutzpah, and therefore typically American; President Polk asking Congress for a declaration of war against Mexico and turning a border dispute into a huge military operation, taking Mexico City and holding it hostage in order to make Mexico sell us the land that’s now New Mexico, Arizona, California, Nevada; then probably McKinley and Roosevelt, building a big navy and beginning to act like a world power.
Those are the five presidents and that time period where you can look back and see precedents for some of what Trump’s doing today. But I don’t want to sound like I’m blessing or condoning what Trump’s up to now, because what might have “worked” back then is not necessarily appropriate for today’s world—and even what we did back then was sometimes ethically very questionable.

Foreign Policy Trends Across Presidencies
BW: You mentioned an expansionist impulse in U.S. foreign policy. Do you see that as something driven mainly by American ideals and institutions—like the Constitution and the structure of the presidency—or by something deeper, like incentives of power and security? And relatedly: if presidents come in with very different instincts—Trump campaigning on avoiding new wars, for example—why does U.S. policy often seem to revert back toward activism anyway?

MO: Expansionism is the word that captures the first half of our history, roughly through the 1890s. The Battle of Wounded Knee in 1890—where Sitting Bull was killed—and that was sort of the end of the wars against Native Americans. It completed the consolidation of the continental United States as we know it today. We had already acquired Alaska from Russia in 1867.
Then we had the Spanish-American War of 1898 where we got Puerto Rico and Guam, and also temporarily involvement in Cuba, and also sort of accidentally and temporarily the Philippines. Then we realized we didn’t really want the Philippines. We didn’t really want to be colonialists. We had reached the natural borders of the country. And everybody after McKinley basically accepted that.
There may have been people who talked about buying Greenland—as Trump would surely say if he were here—but nobody made it a centerpiece of their foreign policy.
So expansionism characterized the first half of our history, and now Trump’s trying to bring it back—and that is a complete break with more than a century of American presidents.

Advice to students: concentration, reading, and protecting the “core hours”
BW: To close, I want to bring this directly back to students. Are there certain habits or skills you developed in undergrad—or other educational pathways—that were particularly formative in your later career, and that you’d recommend students follow?

MO: I’ve never been content with my skill set or my research strategies. I’ve always felt I could be better—always felt I could improve.
Perseverance and putting in the hours is a big part of my strategy, if you will—my recipe.
I think also having some background in science and math, and history, has been good. I don’t call myself a political scientist. I have a lot of qualms about some aspects of American political science—how it’s taught, how it’s conceptualized. I like cleaner, simpler analysis, as you do in physics and math, and as you do in history. Political science is more about inventing concepts that try to explain things. There’s utility to that, but I find it secondary to my research bent and my identity as a scholar.
I try to read a moderate amount, and I try to protect hours in my life. This is not so much a concern for students—students are good at this. Students are often better at this than older adults into our careers, because we wind up getting pulled in a million directions: immediate debates, meetings. Even at think tanks, there are scholars who don’t protect two to four hours a day for research, reading, and writing. But I try to do that.
Sometimes I have to be ruthlessly protective of my time. I don’t do breakfast meetings unless I absolutely have to. I do a little bit of work on the weekend to maintain momentum—not so much that I want to devote the whole weekend to work, but if I’m in the middle of a project, I’ll often devote both weekend mornings to work.
I try to go into the office later in the morning if I can, and do two or three hours of research and writing at home first—especially if I’m in the chunky part of a book project.
So: willingness to be a little tunnel-visioned—stubborn about protecting time for those core skills.
I try to remember when I was a student—when I learned how to concentrate and apply myself—probably starting senior year of high school and all the way through grad school. Again, students are often better at this than older adults.
The ability to work through a lot of literature, read a lot of pages—develop some skimming skills, but also, for some material, read it thoroughly—sit down with it, think about it, let it imprint on the brain. Those skills are important. Finding good books, good authors that become your lodestars—how to think about certain subjects—that’s important. Keep coming back to big ideas and concepts that help you understand a field.
To simplify: science and math have been good; history has been good. They’re matter-of-fact fields that have been good for my brain—teaching me how to think and giving me substantive knowledge and methodology to fall back on. And protecting several hours a day for core research, reading, and writing—that would be my guideline.

Books that shaped him
BW: Finally, Dr. O’Hanlon: what’s a book that influenced your life and your work the most—and why?

MO: It’s a good question. I could give several answers, but you wanted one, so I’ll fall back on something specific.
If you ask me on a different day, I might not give this answer. But I love a history book about the Civil War era by James McPherson called Battle Cry of Freedom. It helped me understand the military parts of the Civil War pretty well—although I did more research on that after reading McPherson, because it’s really more of a societal and cultural and economic and political history leading up to that period.
That period—like a lot of people—I find it fascinating, and obviously excruciating for what it did to the country, but there’s an intrigue about it that’s alluring. McPherson did that—and he was a professor at Princeton when I was there. I’m still kicking myself, but I never took his course. I never even met him. Anyway, it’s a beautiful book. I really, really like it.
And a similar book—I’ll cheat a little bit—is William Shirer’s The Rise and Fall of the Third Reich, about Nazi Germany. Shirer started as a journalist living in Germany after World War I and saw a lot happen. Again, a complex history weaving together politics, people, culture, society, and military matters—and of course a terrible story in the end.
Those were big-idea books that took on crucial periods and wrestled with what was happening and what might have happened differently if people had made better choices.
So I guess those are a couple that you probably wouldn’t get from most political scientists, because these are pure history books. But that tends to be what I like. History has been on my mind a lot the last five or six years.