The age of empire | Rise to world power (1890-1945) | US History | Khan Academy

So I have a map here of United States possessions in the Pacific and in the Caribbean today, and they're kind of all over the place. I mean, some of them are pretty tiny. There's Guam, which is just barely a little speck on the map, and American Samoa. And more well-known would be the Hawaiian Islands, right? The one of the 50 states of the United States.

Have you ever wondered why the United States has islands in the middle of the Pacific? I mean, this is thousands of miles from the mainland of the United States. So, what's the deal? Did the United States just want access to somewhere to get a tan, and maybe buy some pineapple? In this video, I want to talk about the very unique historical circumstances under which the United States acquired a bunch of territory outside of the borders of the lower 48 states, or how, in other words, the United States became an empire.

An empire, or imperialism, is the practice of having political or economic control over a territory that is outside the boundaries of your nation. So when did this happen, and why did this happen? Let me give you a little background on the run-up to the United States becoming an empire.

The Civil War ends in 1865, and while that is a conflict just within the United States, right? The definition of civil war—the Civil War has kind of an interesting effect on the United States's economy. Because, for the course of the Civil War, the North really ramped up their industrial production to win the war. So they build railroad tracks, and they have factories that help them build the armaments that are going to help them with victory in the war.

Well, after the war, all of these factories, all these railroads still exist, and they're turned to different purposes. So over the course of the late 19th century, from the end of the Civil War, really up until, you know, even 1900 and beyond, the United States becomes the leading industrial power in the world. So, they make more stuff than anybody else, and this is one of the reasons why so many immigrants are flocking to the United States in this time period—because there are jobs and factories.

But even though the U.S. was acknowledged as this great industrial power, it was not really acknowledged as a world military power. The number one power in the world at this time is England. This is the end of the Victorian era. None of the nations of Europe think of the United States as an important power in the world. I mean, if you were a diplomat from France and you got a diplomatic posting to Washington, D.C., that would be like getting a diplomatic posting on the moon. There is nothing going on there; nobody is interested. You'd much rather be in Vienna or London.

But another reason why the nations of Europe are such important world powers is because of their own investment in imperialism. So let me show you a map of the world in 1914, which is kind of after this age of imperialism, but it gives you an idea of how much territory Europe had gobbled up in this time period. So this is the rest of the world in this time period, and we're talking about kind of the period from about 1880 to 1900.

In this time period, the powers of Europe really competed with each other to take over territories in the rest of the world, and these would have been developing nations—nations that did not have the firepower to compete with Europe—and they were generally nations with a lot of natural resources. So in the mid-19th century, there had been explorers going throughout Africa. This is the period of Dr. Livingston, I presume—and Dr. Livingston reports back to England that there is a lot of stuff in Africa.

We're talking about diamonds, and gold, and rubber. And elsewhere in the world, in India, there's tea. So in the 1880s and 1890s, Europe scrambles for territorial control of Africa. You see England here in South Africa, and France up here in Northwest Africa, and then, of course, you've got England in India and Australia; and, you know, they're even fighting for influence in China.

They had two main reasons for wanting these colonies abroad. One is, as we said, their natural resources, so they can take all the raw materials, the unfinished goods, to run the empire. And then they can take that back up to Europe and process it. So it's a cheap source of stuff for their industrial production. The other thing they want is markets. So, all of these territories, all of these colonies, have people in them who can buy the products from the European nations.

As their factories produce more and more stuff, they need more and more people to buy those things, or they're going to stagnate economically. So, this is where the United States comes in. In the late 19th century, the U.S. has become this leading industrial power. They feel like they're not getting any respect from Europe for being pretty big dogs, but they also start looking at this scramble for Africa, this scramble for colonies in the world, and they think maybe the United States should get in on this game.

They have a couple of reasons for doing this. One of the reasons for doing this is the idea of expanding the frontier. So, in the late 19th century, there was a pretty famous historian by the name of Frederick Jackson Turner. What Turner has to say really troubles a lot of people. He says Manifest Destiny is done.

So, Manifest Destiny, you'll recall, is this idea that God wanted the United States to occupy the North American continent from Atlantic to Pacific. As of 1890, the census showed that there was pretty much even population distribution all the way to the Pacific Ocean. So this process of conquering the frontier, that many white Americans thought was really crucial to the American spirit, was over.

So, what is the United States going to do? Culturally, they pride themselves on being a pioneering people, but along with that goes the same sort of quest for new markets that Europe is going through in the same time period. So, if the United States is the world's leading industrial power, and they did that by conquering the frontier, building railroads, finding new people to sell the products of their factory to, what's going to happen if they have nowhere else to expand?

Relentless expansion is kind of the backbone of American capitalism, and so people started to worry that if expansion is done, then the American industrial project is going to falter with no new markets to conquer. All right, so those are the economic and cultural explanations for why the United States became interested in being an imperial power at the end of the 19th century.

There are also some military explanations. So let me take you back to a map of the Pacific. So, in 1890, this man named Alfred Thayer Mahan published a book called "The Influence of Sea Power Upon History," and Mahan's thesis was that all the great nations of history since time immemorial had gotten their greatness through a domination of the seas.

So, he says that if the United States really wants to be a world power going forward, they're going to have to make some serious investments in their navy. He says first they're going to have to build a really powerful naval fleet, which has never really been the bread and butter of America's military. I mean, up until this point, the United States Navy was like five leaky boats.

So, he says they have to build a powerful navy and that you should consider putting a canal somewhere across Central America. So that if a ship is in the Atlantic, it doesn't have to go all the way around South America to get to the Pacific, it can just cut this corner here. And the last thing that Mahan says is that the U.S. is going to need friendly ports all over the world so that this navy can dock, refuel, take on new supplies.

Because if your ports are only on the edges of the United States, it could take you days and days and days to make it all the way over to Asia. So, Mahan says we need good harbors along the way. And you know what's a really great harbor? Pearl Harbor in Hawaii. It's one of the best harbors in the world.

Basically, in the future, the U.S. government is going to do exactly what Mahan says. In between 1890 and 1914, the United States increases their investment in the navy by a power of seven. It's 22 million dollars only in 1890. By 1914, they're putting 140 million dollars a year into their navy. They will move forward with this plan to build a canal somewhere in Central America—hint, hint, it might be in Panama—and they will annex ports all over the Pacific and also in the Caribbean to take care of their new, powerful navy.

So, in the late 19th century, the U.S. is really poised to enter into world politics as a major world power. In the next video, I'll talk about the Spanish-American War of 1898 and how that led the United States to become an empire.