I suspect that the supremacy clause makes this a grey area.

Simplified: you can make something illegal locally, but federal law will almost always win out.

Sure but the end result of that is simply that local agencies could not legally use this technology, not that they can just ignore local laws because the federal government wants them to. The federal government can maybe force Flock to turn over data, but local governments then cannot use Flock in accordance with Illinois law. In the case of Illinois, this is indeed causing some local governments to reconsider their Flock contracts.

	▲	dghlsakjg 3 hours ago \| parent [-]
		Well, not quite. The local governments are in compliance with state law until the feds use it for immigration enforcement. Then the supremacy clause takes over and more or less nullifies it. As long as it isn’t the local agency using it for enforcement, then they are in the clear. I think that Flock contracts are getting cancelled due to unpopularity, not because of compliance worries. Can you point to any actual cases where enforcement of the state law led to a termination of service?