Oh, aren't you clever ? Your absurd constant repetition of "The law cannot compel people to act on behalf of the federal government" is like a car stuck in the mud, and spinning its wheels, and going nowhere.
For the 10th time, the law can stop state & local govts from stopping their police from acting on behalf of the federal government, and arrest then when they do that. Thatks what it says. Can you read English ?
It and also execute sanctuary bums if their laws contributed to people getting killed.