You tell the Japanese that you know their fleet is at sea, ready to attack. You position our ships out at sea to intercept the Japanese fleet. You transfer B-17s to MIdway to strike at the Japs..You tell them all this is happening..they withdraw...do we then declare war? nope..
The Japanese were going to attack Hawaii come hell or high water. It was only one part of a coordinated series of air strikes and invasions also hitting Malaya, the Phillipines, the Dutch East Indies, Guam, and Wake all within a 12 hour time frame.
Also we did not have the forces to attack Kido Butai available in Hawaii at the time. Nor did we have enough search aircraft available. What we did have were enough fighters (P-40s and P-36s) to severely maul the attack waves as they came in.
But since there was no air warning system set up by the commander of the Hawaiian Department they were useless.