Friday marks the International Day of the Girl. The United Nations has set aside October 11 to focus on the discrimination and abuse that women and girls suffer throughout the world.

One brutal crime that demands a far more intensive worldwide response is commercial sexual exploitation. This problem is of crisis proportion, and each time it happens it amounts to selling the rape of a child for profit.

This illicit global industry has begun to receive some of the attention its victims desperately require. But a blind spot remains: American girls on American soil.

It is happening here, to our girls. By conservative estimates, 100,000 American children are trafficked each year. Many, though not all, of these victims lived at the margins of American life before they were trafficked. They were struggling against poverty, and often had histories of trauma, abuse, violence or neglect.

So although October 11 has been designated as a day of international focus, Americans should also turn their attention inward — where it is often most painful to look.