There was a radar installation operating in Hawaii on December 7th. It even picked up the incoming Japanese planes. The problem was that they were mistakenly assumed to be a flight of B-17s that were expected to arrive that same day.
Maybe the location of the radar unit didn’t make any difference, but at a higher elevation it might have detected the planes at a greater distance, and in that case they might have had more time to figure it out.
In any case, it seems to me that both in Hawaii in 1941 and today on our southern border, national security should override fanatically strict environmental policies.