Interstate anything is federal.
But I would not fight this "ZOMG it illegal" angle very hard. Valid evidence is still valid evidence and claim exclusionary rules for this sort of thing would be tantamount to claiming you have something to hide.
The real point is: there's nothing to hide here. Nothing Walker said is indicative of a crime, unethical behavior or bad policy.
Please stop being so smart and wise. It makes the rest of us look bad.
