Short answers, pulled from the story.
Operation Cartwheel was a major Allied military operation in the Pacific theater of World War II that began in February 1942. The campaign aimed to capture Rabaul on the island of New Britain from Australian troops who had previously held the location.
General Douglas MacArthur formulated the strategy known as the Elkton Plan to capture Rabaul using bases in Australia and New Guinea as staging points. Army Chief of Staff George C. Marshall sought a compromise that divided the drive toward Rabaul into three stages under different commands.
Operation Chronicle began between the 23rd and the 30th of June 1943 when units of the 112th Cavalry Regiment landed unopposed on Woodlark Island. Simultaneously, elements of the 158th Infantry Regiment secured Kiriwina Islands without resistance.
The island of New Georgia held 10,500 Japanese defenders who made the location vital due to an airfield at Munda Point. Allied losses reached 1,094 dead and 3,873 wounded while Japan lost 2,483 men during the fighting.
Officials decided to bypass and isolate Rabaul rather than attempt capturing the base garrisoned by tens of thousands of Japanese troops. Soon afterward commanders made the decision to bypass Kavieng as well despite initial objections from MacArthur.
Allied planes shot down between 200 and 300 Japanese carrier aircraft during raids on Rabaul stripping Japan of irreplaceable veteran pilots. From February 1944 onwards Japanese declined to provision Rabaul with fighters or bombers for the rest of the war due to non-stop bombing by land-based Allied airplanes only a few hundred miles away.