The Allies didn’t actually win the battle — Tokyo considered it a tactical victory because its forces had sunk the largest ship — but they did enough damage to take Japan’s newest carriers out of commission, which proved to be a decisive advantage at Midway. And it introduced our naval leaders to the new realities of warfare on the seas.
“This was the first naval sea battle where the ships never see each other — they were five hours apart by sea, 20 minutes by air. The devastation that’s wrought by air shows everybody that naval warfare has totally changed,” says Berry. Coral Sea also halted Japan’s advance toward Australia — and it is something the Aussies have never forgotten.
Fox news discussion here, putting it into the context of the fall of Corrigidor.
As the Japanese tightened their grip on Bataan, President Franklin Roosevelt ordered MacArthur to leave Corregidor and proceed to Australia, ostensibly to take command of a relief expedition. His return to the Philippines would take years, but MacArthur’s dramatic escape by PT-boat propelled him into legend as the hero the American public desperately needed during the uncertain early months of the war. Back in the Philippines, there was no hero worship. Faced with starvation, forces on Bataan surrendered early in April. Corregidor hung on until May 6. Where did this disastrous defeat leave America and its allies? As MacArthur hunkered down in Australia and mourned the fall of Corregidor, two aircraft carriers of the US Navy sailed into the Coral Sea to counter an invasion aimed at Port Moresby on New Guinea that threatened Australia itself.
which is why Australians remember that battle: without it, they were next.
In the South Pacific the Japanese Army was keen to extend the perimeter to provide defence in greater depth for the base at Rabaul and also to cut the lines of communication between Australia and the west coast of the United States. Japanese operational doctrine held that advances should always be made under cover of land-based aircraft.
This doctrine governed the choice of new targets and had been rigidly adhered to in operations in China and in the Pacific. Techniques had been developed to bring newly captured airfields into use as quickly as possible.
In this context the Solomon Islands could be seen as an opportunity for expansion south to New Caledonia, the New Hebrides and Fiji; they could also be seen as a highway for an Allied offensive aimed at Rabaul. Port Moresby was also in air striking range of Rabaul and the Japanese were becoming concerned with the build up of Allied air power in the area.
Conversely, its occupation would lead to Japanese aerial dominance of north-eastern Australia. Nauru and the Ocean Islands would also be occupied. Consequently the Japanese put in train Operation MO. The object of this operation was the capture of Port Moresby in New Guinea and Tulagi in the southern Solomons.
Strategypage discussion of the battle. includes noting the backstories usually not mentioned: That the Japanese rigid command structure resulted in lost opportunities, and the US lack of experience led to errors.
And that the US was faster at repairing ships and getting them battle ready.