The Japanese Imperial General Headquarters considered invading Australia in early 1942 but decided against doing so in February that year, as it was judged to be beyond the Japanese capabilities, and no planning or preparations were undertaken. Instead, in March 1942 the Japanese military adopted a strategy of isolating Australia from the United States and preventing Allied offensive operations by capturing Port Moresby, the Solomon Islands, Fiji, Samoa and New Caledonia. An attempt to capture Port Moresby by an amphibious assault, Operation Mo, was thwarted by the Battle of the Coral Sea in May 1942. A month later, most of the Japanese carrier fleet was destroyed in the Battle of Midway, further reducing the possibility of major amphibious operations in the South Pacific. Following this, the Japanese began to consider an overland advance on Port Moresby.