Sayfullo Saipov did not arrive in the United States alone. In 2009, he was one of 3,284 lucky residents of Uzbekistan to win the green-card lottery. That same year, the lottery granted green cards to—among others—2,894 Albanians, 590 Australians, 1,154 Bulgarians, 4,307 Kenyans, and 2,331 Turks; for a total of 50,000 admissions.

Good and bad qualities are randomly distributed in the human population, and randomly is how the diversity lottery distributes its rewards. So it should not be very surprising that one member of the class of ’09 proved to be a mass-murdering terrorist. The lottery imposes no requirements of skill, not even knowledge of English. Convicted criminals are excluded, as are persons affiliated with known terrorist groups. There is a basic health requirement. Beyond that, the system is—as it says right in the title—a lottery, open to anybody with a working Internet connection and $30 for the entry fee.

You might wonder: Why do we do this? Why would the United States forswear the right to choose the people it admits, to assess them for what they can contribute to the welfare of the community to which they seek entry?