In 1944 no one knew that there was going to be an atomic bomb coming along like a deus ex machina. It made sense to drive the Japanese back bit by bit – a ground invasion of the home islands, which is what was planned, would have been a horrible slaughter if the Japanese would have still had large armies in the Phillipines to draw on.

If we want to write alternate histories we can imagine what it would have been like for the US to have built 1000 submarines and waged war by simply cutting the home islands off completely, but I don’t think that was a realistic option at the time. As it was their shipping was pretty effectively eliminated, but as we found with Saddam under sanctions a blockade with no invasion can drag on forever.