The six-raid sequence from the Gilberts to Japan

The campaign opened with the Marshall-Gilbert attacks on 1 February, followed by Rabaul on 20 February, Wake on 24 February, Marcus on 4 March, Salamaua-Lae on 10 March, and the Doolittle Raid on 18 April. Most of these operations used a single carrier, while the final strike combined Hornet and Enterprise. Richardson opposed keeping the fleet at Pearl Harbor without adequate security and support. In this account, Navy exercises had repeatedly penetrated the Army's defenses there over the preceding decade. He continued advising King, Kimmel, and Nimitz, recommending attacks that exposed Japanese vulnerability and forced a defensive response. The raids progressively moved the threat from the defensive perimeter toward the home islands.