Brooks: What if the prison system were its own country?

You already know that the United States locks up a higher percentage of its population than any other country in the world. If you look at local, state and federal prison and jail populations, the United States currently incarcerates more than 2.4 million people, a figure that constitutes roughly 25 percent of the total incarcerated population of the entire world.

A population of 2.4 million is a lot of people -- enough, in fact, to fill up a good-sized country. In the past, the British Empire decided to convert a good chunk of its prison population into a country, sending some 165,000 convicts off to Australia. This isn't an option for the United States, but it suggests an interesting thought experiment: If the incarcerated population of the United States constituted a nation-state, what kind of country would it be?

Here's a profile of Incarceration Nation:

Population size: As a country -- as opposed to a prison system -- Incarceration Nation is on the small side. Nonetheless, a population of 2.4 million is perfectly respectable: Incarceration Nation has a larger population than about 50 other countries, including Namibia, Qatar, Gambia, Slovenia, Bahrain and Iceland. And though the population of Incarceration Nation has dipped a bit in the last couple of years, the overall trend is toward growth: over the last 30 years, the incarcerated population of the United States has gone up by a factor of four, making Incarceration Nation's population growth rate more than double that of India.

Geographic area: This is a tough one, since I haven't found any way to accurately measure the physical space occupied by Incarceration Nation. We have to do some educated guessing here. There are more than 4,500 prisons in the United States. Let's assume that each of those prisons takes up about half a square mile of land -- a reasonable (and probably quite low) estimate given that most prisons are, for security reasons, surrounded by some empty space. That gives Incarceration Nation an estimated land area of about 2,250 square miles: small, but still larger than Brunei, Trinidad and Tobago, Luxembourg, Bahrain and Singapore.

Population Density: No matter how you look at it, Incarceration Nation is a crowded place. If we assume a land area of 2,250 square miles, it has a population density of roughly 1,067 people per square mile, a little higher than that of India. Of course, the residents of Incarceration Nation don't have access to the full land-area constituting their nation: most of them spend their days in small cells, often sharing cells built for one or two prisoners with two or three times that many inmates.

In 2011, federal prisons were operating 39 percent above capacity; in many state systems, overcrowding was much worse. (In 2011, the U.S. Supreme Court found that overcrowding in California prisons was so severe it constituted "cruel and unusual punishment".)

Demographics: A nation of immigrants: Like many of the smaller Gulf States, Incarceration Nation relies almost entirely on immigration to maintain its population. You might even say that Incarceration Nation is a nation of displaced persons: most of its residents were born far away from Incarceration Nation, which has a nasty habit of involuntarily transporting people hundreds and sometimes thousands of miles away from their home communities, making it extraordinarily difficult for residents to maintain ties with their families.

In New York, for instance, one study found that "70 percent of incarcerated individuals are in prisons over 100 miles from their homes" -- often in "isolated rural areas that are inaccessible by direct bus or train routes."

Birthright citizenship? Though most residents are immigrants and displaced persons, an estimated 10,000 babies are born each year in Incarceration Nation. Most of those babies are deported within months, generally landing with foster families. But Incarceration Nation does have its own form of birthright citizenship, if you can call it that: as many as 70 percent of children with an incarcerated parent end up incarcerated themselves at some point.

Gender balance: International attention to gender imbalances has tended to focus on China, India and other states, but Incarceration Nation has the most skewed gender ratio of any country on Earth: men outnumber women by a ratio of about 12 to 1.

Racial and ethnic makeup: If Incarceration Nation were located in a geographical region matching its racial and ethnic makeup, it would probably be somewhere in the Southern Hemisphere, perhaps near Brazil. Roughly 40 percent of the incarcerated population is of African descent, another 20 percent is of Hispanic descent, and the remaining 40 percent are Caucasian or mixed. For the average American, this means that one's odds of spending time in Incarceration Nation depend greatly on gender and race: a white woman has only a one in 111 lifetime chance of ending up incarcerated, while a black man has a whopping one in three chance.

Health: Incarceration Nation doesn't do so well here. One recent study found that the incarcerated are "more likely to be afflicted with infectious disease and other illnesses associated with stress." Tuberculosis rates, for instance, are 50 to 100 percent higher for inmates than for the general U.S. population. (If Incarceration Nation were a real country, it would have the highest TB rate in the world.) More than half of Incarceration Nation's citizens are mentally ill, with depression rates roughly on a par with those experienced by citizens of Afghanistan. Another recent study found that for every year spent incarcerated, life expectancy dips by two years.

Human Rights: Incarceration Nation is a police state. 'Nuff said.

Economics: Incarceration Nation doesn't make it easy for outsiders to understand its unique economy, but it's possible to gather a few data points.

Per Capita Spending: Judged by per capita government spending, Incarceration Nation is a rich country: its government spends an average of about $31,000 per year on each incarcerated citizen. (State by state, costs vary. Kentucky and Indiana spend less than $15,000 on each inmate per year, while in New York State, the per capita cost per inmate is more than $60,000 a year. In New York City, per capita costs for jail inmates reach an astronomical $168,000 per year.)

Internationally, only little Luxembourg spends as much on its citizens as Incarceration Nation; among the generally wealthy states of the Organization for Economic Cooperation and Development, average per capita spending is under $15,000, and Sweden, France, Germany, Canada, the United States and the United Kingdom all spend under $20,000 per year on each citizen.

Gross Domestic Product: Incarceration Nation doesn't have a GDP, per se, but that doesn't mean it doesn't turn a profit -- sometimes, and for some people. For American taxpayers, aid to Incarceration Nation is pretty expensive: looking at just 40 U.S. states, the Vera Institute of Justice found that the cost to taxpayers of incarceration in these states was $39 billion. Overall, federal and state governments spend an estimated $74 billion on prisons each year. (This doesn't count spending on state and local jails.) How much is $74 billion? It's higher than the GDP of more than half the countries in the world, including Lebanon, Paraguay, Nepal and Lithuania.

Some people make a lot of money from Incarceration Nation. Incarceration Nation employs about 800,000 people as prison guards, administrators and the like -- almost as many people as are employed in the entire U.S. automobile industry -- and in some rural areas, prisons are the main employers. But the real money goes to the operators of private prisons and the companies that make use of prison labor.

Overall, private prisons house roughly 10 percent of Incarceration Nation's residents, and large private prison companies (such as CCA, the Geo Group, and Cornell Companies) boast impressive annual revenues. In 2011, for instance, CCA -- which urges potential investors to take advantage of "highly compelling corrections industry dynamics" -- has an annual revenue of over $1.7 billion, and its CEO, Damon Hininger, was the happy recipient of some $3.7 million in executive compensation in 2011.

Labor Standards: If you think low labor costs in countries such as China and Bangladesh are a threat to U.S. workers and businesses, labor conditions in Incarceration Nation will dangerously raise your blood pressure. Take UNICOR, a.k.a. Federal Prison Industries, which employs 8 percent of "work eligible" federal prisoners. Hourly wages offered by UNICOR range from 23 cents an hour -- about on a par with garment workers in Bangladesh -- to a princely $1.35 for "premium" prisoners, comparable to the hourly wage of Chinese garment workers. That's a good deal less than the $2 average hourly wage for a manufacturing worker in the Philippines, or the $6 an hour average wage for Mexican manufacturing workers.

Who benefits from these low wages? The U.S. Department of Defense, for one. The DOD is UNICOR's largest customer; in fiscal year 2011 it accounted for $357 million of UNICOR's annual sales. UNICOR makes everything from Patriot missile components to body armor for the DOD: In September 2013, for instance, the DOD announced that the Army has awarded UNICOR a "$246,699,217 non-multi-year, no option, firm-fixed-price contract . . . to procure Interceptor Body Armor Outer Tactical Vests for various foreign military sales customers."

This is a great deal for everyone except the population of Incarceration Nation, since they're stuck with forced labor at wage levels that would make many third world employers blush. No one likes to talk about this, of course: "We sell products made by prison labor" isn't the kind of slogan likely to generate consumer enthusiasm. But to those in the know -- as an online video promoting UNICOR's call-center services boasts -- prison labor is "the best-kept secret in outsourcing."

Maybe Incarceration Nation really is a foreign country.

Brooks is a law professor at Georgetown University and a fellow at the New America Foundation. She served as a counselor to the U.S. undersecretary of defense for policy from 2009 to 2011 and previously served as a State Department senior adviser.