On last night's Colbert Report, an amazing moment occurred when Stephen Colbert raised a major social issue that U.S. mainstream media assiduously ignore: the huge U.S. prison population. The issue quickly disappeared due to the apparent ignorance of Stephen's guest: Assistant Secretary of State Michael Posner, in charge of "Democracy, Human Rights and Labor."

In a sometimes jokey interview, with Posner discussing China's various human rights abuses (including prisoners), Colbert tried to steer the conversation to human rights problems in our own country.

COLBERT: We've actually got more people in prison than China does.

POSNER: Well I'm not sure that's true.

Colbert's assertion is indisputably true. Posner's denial is false. Does the State Department's man in charge of human rights not know the facts?

According to statistics gathered by the authoritative International Centre for Prison Studies in London, the United States has by far the largest prison population in the world: almost 2.3 million people behind bars. China's prison population is second in the world: roughly 1.6 million.

The United States is also number 1 in the world in its "prison population rate": 748 inmates per 100,000 citizens. Russia is 3rd. China is tied for 114th.

This is a U.S. human rights problem of enormous proportions. Our bloated prison population has many causes: the "drug war," mandatory minimum sentencing, poverty, racism. And there are corporate profits to be made from "The Prison-Industrial Complex" -- as independent journalists like Eric Schlosser began documenting a dozen years ago.

Wouldn't it be great to see this issue tackled by some mainstream TV voices . . . other than Stephen Colbert?