What Kimmel and Short could do without a declaration of war

What could Kimmel and Short do after USS Ward's report without provoking war?

They could raise readiness, launch an alert combat air patrol, operate radar, and activate observers without initiating hostilities.

The available system was rudimentary but usable. Commanders could place aircraft and antiaircraft units on alert without ordering an offensive action against Japan. Radar contacts and reports from the coastal observer network could guide alert fighters toward unidentified formations. The Royal Navy's move toward wartime readiness before Britain entered the European war provides a comparison for defensive preparation short of initiating hostilities.