The Philippines is the largest colony that the United States held in 1940, or indeed has ever held, and it’s attacked in the same attack as Pearl Harbor, just a few hours apart. It’s a really interesting set of questions that Roosevelt has to answer, to try to convince the mainland public that this is something that should lead to war. I found it so fascinating to watch FDR noodle in his drafts with that, and to try and work it out on the page.

In the first draft, he describes the event as an attack on Hawaii and the Philippines, which it is, although he still omits Guam. And then you can just see him almost rethinking that and wondering if it’s going to work. We don’t know what was in his mind at the time, but I strongly suspect that he was aware of how many in the mainland were not enthused about a defense of the far western territories of the United States. Opinion polls of the time indicate that even when we’re talking about Hawaii, a small majority of people were actually supportive of the US military defending Hawaii; those numbers are smaller for the Philippines and Guam.

So you can see FDR crossing out the Philippines as a prominently listed target, and trying to turn the speech into a speech about Hawaii, which I suspect he thinks will work a little better for his narrative purposes — it’s whiter, it’s closer to the US mainland, and in a pinch, it can be rounded up to quote-unquote “America.” In fact, he inserts the word “American” into his speech — it’s one of the last edits he makes, so that instead of just describing it as an attack on the island of Oahu, it’s an attack on the American island of Oahu.

Ultimately this serves his purpose, as it allows him to make the statement that the empire of Japan has attacked the United States of America. That’s the thing he wants his audience to understand.

There are so many ways in which the US overseas territories are hidden from view, and this is a chance for you to see it in an extremely direct and consequential way, because the sense that the Philippines was foreign to the US was held by the mainland public, and to some degree by leaders in Washington, throughout the war. It had overwhelming, lethal consequences for the Philippines.

World War II was the bloodiest event ever to take place on US soil, and a lot of that has to do with the strategy adapted by the US vis a vis the Philippines, first allowing the islands to become a sacrifice zone to Japan, which would then permit the United States to gather its forces and concentrate on the European theater. And second, when the US “liberated” the Philippines, it did so by fairly general bombing and shelling, which ended up killing Filipinos who were US nationals at the same time as it killed Japanese. That strategy saved the lives of mainland soldiers, but it was profoundly destructive to the largest colony that the United States held. In a month, the US and Japanese forces decimated Manila, which was the sixth-largest city in the [US’s total territorial holdings].

I don’t see it as a sudden onset of altruism on the behalf of the United States. I don’t see it as a lack of interest in wielding influence in the world. Rather, it has to do with choices made in Washington about how to wield that influence, what sort of territorial footprint the United States will require to be the global hegemon.

Two things happen in the 1940s and after that help set the shape of power. One is a serious, worldwide revolt against empire by colonized peoples, both within and without the Greater United States, driving the cost of colonialism up. At the same time, the United States masters several new technologies that allow it to project power without holding large populated colonies, and those technologies drive the demand for colonialism down.

That doesn’t mean that the United States no longer needs any land: rather, it doesn’t need large swathes of land and can make do with small splotches. I describe it as the emergence of a “pointillist” empire: if you look at all of the US overseas territory today, if you were to mash it all together, you would have a land area that’s less than the size of Connecticut. That’s all the colonies and military bases that we know about.

Nevertheless, that’s hundreds of extremely important points that the United States controls around the Earth’s surface, so it’d be a mistake to round those down to zero and to not really understand how crucial they are to the exercise of US power today.

In the early twentieth century, you could imagine two possible visions for power. One is the Teddy Roosevelt vision, according to which the way to express power is to claim land, subdue the people who live on it, and fill that land with white settlers. Herbert Hoover has a different vision for US power, which is not power exerted through territorial empire, but power exerted through smoothly operating markets.

He spends an enormous amount of time thinking about how to make those markets smoother, and he’s particularly interested in recasting objects so that the world economy can operate more smoothly. He oversees a number of national standardizations that become the seeds for global standardizations, including, mostly famously and impressively, the standardization of screw threads.

In the nineteenth century, the US was an industrializing country, and it used screws as the universal fastener. But different manufacturers made different screws that had different angles, different diameters. This is extraordinarily difficult if you’re trying to work in a nineteenth-century economic context: let’s say that a machine breaks and you need a screw, you need to go back to the manufacturer, and if that manufacturer is out of business, you’re screwed.

Herbert Hoover standardizes screw threads in the United States at huge economic cost to the existing manufacturers. But that screw thread that Hoover pushes then becomes the basis for global screw thread, which is to this day at a sixteen-degree angle. So, in some ways, Herbert Hoover is a more prescient prophet of the shape of US empire than Teddy Roosevelt.

Jefferson and Washington were very happy to see their country grow, but they didn’t expect for that to happen quickly. What they didn’t fully grasp, but Ben Franklin did, was just how explosively the settler population was growing. The early United States was demographically unprecedented. There hadn’t been a country in modern history growing at the sustained rate that it was, and so it took political leaders a little bit to wrap their heads around that fact.

The enormous population growth, partly from immigration but largely just from childbirth, propelled the borders of settlement westward more rapidly than Jefferson had any reason to expect. In 1803, when Jefferson was contemplating the Louisiana Purchase, he imagined that the land acquired under the purchase would be used mainly for Native Americans, and that the part of that land required for white settlement would initially just be a small patch in New Orleans. He didn’t think that there would be that much population pressure — he imagined that whites would settle compactly.

They absolutely didn’t, and the transition from that vision of expansion to the one that was more firmly in place by the Jacksonian period was a decisive one. By that period, it was clear that the United States would be committed to some form of settler-colonialism involving large-scale, repeated, and frequent displacement of native peoples. What’s extraordinary about the US in the mid-nineteenth century is how many Indian removals are compounded by Indian removals right after. How many groups are given a “permanent” residence west of the Mississippi, and then within half a generation or so, are asked or compelled to leave once again?

Often the debate about whether the United States is an empire is a debate over its character, whether it’s a force for liberation or domination in the world, often simply whether it’s good or bad. In my book, I didn’t seek to vilify or venerate the country, but rather to describe it, especially its territories and colonies and outposts.

My biggest intervention is not to change anyone’s sense of who the United States is in terms of its character, but to change people’s sense of where it is geographically. For a lot of people, that might be a big change, because normally when historians think of the United States, they tend to just think of the mainland, and treat US history as largely that. But those aren’t the legal borders of the country, and when you exclude everything outside of the mainland from your analysis, you get a truncated history, and a lot of things become harder to explain when you can only see part of the country. Whereas if you see the full thing, they become transparently relevant.

One example is Puerto Rican nationalism. Throughout the middle decades of the twentieth century, Puerto Rican nationalism was a major force — not just on the islands, but on the mainland. It has led to seven city revolts in Puerto Rico that culminated in an assassination attempt on President Truman. Puerto Rican nationalism led to a shooting of five Congress members in the US House of Representatives. The fact that this is often a surprise to people, even who have PhDs in US history, strikes me as an example of the ways in which this story gets truncated.

Another important example is 9/11. Afterwards, the 9/11 Commission wrote its report, and the authors said something to the effect of, “It was a surprise that someone so far away — i.e., a Saudi man in Afghanistan — would have such strong views on the United States.”

But of course, from Osama bin Laden’s perspective, the United States wasn’t far away. His main focus was a US military base, a base that his father had helped to build, a base that he had claimed to have bombed, a base that seemed to him to be the implanting of foreign infidels in the land of Mecca and Medina in Saudi Arabia.

Whenever Osama bin Laden explained why he was making war on the US, he brought up the military base in Saudi Arabia. But if you just think of the country as the mainland, and not as somewhere that has outposts and colonies and dots all over the planet, it’s easy to not get that. It’s easy to think of Osama bin Laden reacting just to the moral character of the country: “They hate us because we’re free,” as Bush said.

But it’s not just 9/11 — there are many events in global history that revolve around the bases. In my book, I talk about the Beatles coming up as a “base band,” working in the shadow of the largest US military base in Europe, which was right outside of Liverpool. I talk about the growth of Sony, which got its start in occupied Japan, emulating US technologies and orienting itself toward the dominant US market. I talk about the movie Godzilla, which in its original Japanese incarnation, Gojira, was a sort of protest film, protesting the United States using Pacific islands to test atomic weaponry.

My point wasn’t to say that bases are uniformly detested wherever they are. Colonialism is always complex. It always involves some amount of participation and some amount of protest. I wanted to tell the story of the bases as rich contact zones, places that do indeed stoke resentment, but also stoke curiosity, and all kinds of complex relationships in the way that the US has planted itself all over the world.

One virtue of the various points within the United States’ empire is their location. They’re in strategically significant locations. Another is that they’re often in legally strategic locations, and so Saipan is US territory, but because it’s part of unincorporated territory, it doesn’t automatically fall under US federal law, and it has functioned in labor history as a sort of standing loophole.

I got very interested in the way that not only did major clothing retailers like J. Crew relied on Saipan, which was otherwise not a particularly convenient place to make clothes, as their source. But I also got really interested in the way in which Jack Abramoff, the notorious lobbyist, latched onto Saipan, as he did onto other colonial contexts, as loopholes to be exploited.

Abramoff was, for some time, the top lobbyist in Washington, but shockingly, he didn’t represent Fortune 500 companies. He represented the Commonwealth of the Northern Mariana Islands, Guam, Puerto Rico, various Native American groups. There’s a reason: he understood that empire is the source of legal anomalies. He was operating on exactly the same logic that John Yu was operating on in fixing on Guantanamo Bay as a place where the US could interrogate detainees under US jurisdiction but free from the strictures of US federal law.

One thing that’s clear is Trump, who often says the quiet parts out loud, has a very clear geographic sense of the United States as the mainland, and a place that is threatened by the foreign world around it. He and his administration are often baffled by parts of the United States that aren’t on the mainland.

Jeff Sessions, extraordinarily, said that he was amazed that a Hawaiian judge, which he said was “sitting on some Pacific island,” could block one of Trump’s travel ban. It’s very hard to make sense of the cacophony of Trump’s foreign policy, but it does seem to be clear that he envisions the US spatially as the kind of place you can and should build a wall around. All the overseas entanglements of the country are things that make him profoundly uncomfortable, and he has a vision of retracting the country to the borders of the mainland.

Trump is enamored by US military force and excited by the violent exertion of it, but he’s so uncomfortable with the entanglement between the domestic and the foreign that nevertheless joint agreements, military bases, overseas territories all seem to discomfort him to some degree. That’s pushed him towards an interesting politics. I can imagine a self-consciously anti-imperialist foreign policy that sought to retract the US empire — less from a fear of the foreign, as it seems to be governing Trump’s instincts, but from a desire for the United States to approach the world as one country among others, rather than as a dominant, hegemonic force.

There’s a kind of irony of Trump’s position, that his fear of the foreign has led him to what on the surface is at times an anti-imperialist position. But that’s not unusual in US history. After 1898, some of the most dogged anti-imperialists, the ones that didn’t want the US to annex overseas territories, were racists, and didn’t want to see the borders grow to encompass more non-white peoples.

I don’t think an anti-imperialism that is based on revulsion towards foreigners, and a desire to limit the United States’ entanglement with any part of the world, is going to be a successful or humane anti-imperialism. It may look more the way the Trump administration’s disregard for Puerto Rico looks, seeking to limit funding in the aftermath of two devastating hurricanes. That is indeed a way for the United States to lighten its presence in its largest territory, but not one that I think would be very welcome to any right-thinking person.