I always see it posed as “we either nuked Japan or we invaded”, but the nukes were absolutely used in preparation for a land invasion. Nuking Hiroshima and Nagasaki fit into the highly controversial US strategy of strategic bombing Japanese industry prior to a land invasion, and they were not even the most deadly of our strategic bombing campaigns against Japan (the fire bombing of Tokyo was worse). A proper invasion of Japan post introduction of nuclear bombs commanded by one of our most infamously nuke happy commanders, Douglas MacArthur, planned to have US troops marching through the radioactive wasteland formerly known as Japan slaughtering anything that resisted them. It wasn’t an either or, we weren’t nuking Japan as an alternative to a land invasion, we were nuking them in preparation for a land invasion