If Mayor Michael Bloomberg was trying to stem the criticism of his constitutionally suspect stop-and-frisk policy over the weekend, he took a rather strange approach with his loopy logic and discredited arguments. Speaking on his weekly radio program, Mr. Bloomberg dismissed the idea that the policy, under which hundreds of thousands of mainly minority citizens are stopped on the streets every year, is racially imbalanced because it singles out people based on race.

Focusing on murders, Mr. Bloomberg said those crimes are mainly committed by minority residents and that witnesses identify the suspects that way. “In that case, incidentally, I think, we disproportionately stop whites too much and minorities too little,” the mayor said. “It’s exactly the reverse of what they say.”

The very idea that white people are being stopped on the streets too often is laughable. But that’s not where the problems with the mayor’s argument end.

The homicide part of it is also problematic. Mr. Bloomberg has often credited stop-and-frisk with bringing the murder rate to an all-time low. But if crime and street stops were strongly related, the murder rate would have gone up last year, when stops went down by about 20 percent.