A few hundred marines who, when the japanese show up, they blow them out of the water. They sink a destroyer or two, damage a light cruiser and provide one of the few bright spots in american newspapers. This is something you're going to see replicated all over the region during this firstJap blitzcreek period.
Japan's rising sun goes supernova and engulfs a huge area of Asia and the Pacific. A war without mercy begins to develop infusing the whole conflict with a savage vibe.