Here's an interesting example of how courts don't pay enough attention to 4th Amendment cross-enforcement issues: The 3rd Circuit's recent opinion in US v. Osorio, decided 12/20/18. Thread below . . . . www2.ca3.uscourts.gov/opinarch/17313… 
Relevant issue in the case: Could municipal officers in Pennsylvania make an arrest on a federal probation warrant? Court says yes, b/c "municipal officers are authorized to execute federal arrest warrants," citing a CA2 and a CA5 case.
But if you look at the two cases, they're precedents saying that *state law* governed whether state officers could execute federal warrants -- based on a reading of US v DiRe and US v. Marsh. In the two states at issue , NY and Florida, state law okay'ed executing fed warrants.
In the new CA3 case, Osorio, it's a different state -- these were Pennsylvania officers. But the Court doesn't consider state law, as the precedents say; it just reads the cases as announcing a rule, " municipal officers are authorized to execute federal arrest warrants."
Whatever the right answer is, there's a lot more going on than the judges are realizing. For more, see my article, "Cross-Enforcement of the Fourth Amendment," harvardlawreview.org/wp-content/upl… /end
