The Allies made it clear that they would only accept an unconditional surrender. That policy is what forced the issue and made the nuclear bombings, "necessary." Without the strict unconditional surrender policy the bombings wouldn't have been, "necessary."
History proves that incorrect. The Army controlled the Government and were more then willing to die to the last man rather then surrender. Their defense plan was to command all civilians to equip themselves with bamboo spears and human wave attack any invasion site until all the civilians were dead or the invaders were driven back into the sea.
After months of fire bombing which crippled their industry and killed over a million civilians they were prepared to issue the above orders. KNOWING they could not feed the population or provide adequate fuel sources for winter they REFUSED to surrender.
After one Atomic Bomb the Army refused to surrender demanding ridiculous terms. After a second they still refused and were over ruled by the Emperor. The Army staged a Coup to seize the tape of the surrender, fortunately for the Japanese people that Coup failed.