The United States imprisons people for drug use and other crimes that rarely result in prison sentences in other nations, helping to explain why a country with 5 percent of the world's population accounts for 25 percent of the global prison population, the New York Times reported April 23.

Offenders in the U.S. also are typically sentenced to longer terms in prison than those in other nations, experts say.

Research from the International Center for Prison Studies at King's College London shows that there are 2.3 million prisoners being held in the U.S., whereas China -- with four times the population -- has 1.6 million prisoners, though this does not count the hundreds of thousands of Chinese thought to be in labor camps or in administrative detention because of so-called political crimes.

The U.S. also leads the world in incarceration rates, with one in 100 adults behind bars. For every 100,000 in total population, the U.S. jails 751 people; worldwide, only Russia comes close, with 627 prisoners per 100,000 population.

Experts say that harsh sentencing laws, the War on Drugs, and even democracy play a role in America's apparent love affair with incarceration. Elected judges, experts note, are more susceptible to public pressure to lock up offenders.

"Far from serving as a model for the world, contemporary America is viewed with horror," according to James Q. Whitman, a specialist in comparative law at Yale. "Certainly there are no European governments sending delegations to learn from us about how to manage prisons," as was once the case.

Most of the increase in the U.S. incarceration rate has occurred since the late 1970s. High crime rates and easy availability of guns play a role. "The assault rate in New York and London is not that much different," said Marc Mauer, the executive director of the Sentencing Project. "But if you look at the murder rate, particularly with firearms, it's much higher."

The U.S. also is more likely than other nations to incarcerate people for nonviolent property crimes -- it is the only advanced nation, for example, to lock up people for passing bad checks. And, of course, the U.S. prison population includes an estimated half-million drug offenders.

If viewed on an annual per-capita basis, some European nations would jail more people than the U.S. But the extraordinarily long prison sentences handed down in the U.S. means that the American prison population remains much higher.

"America is a comparatively tough place, which puts a strong emphasis on individual responsibility," said Whitman. "That attitude has shown up in the American criminal justice of the last 30 years."