Japan's Navy was depleted and the islands in ruin when we nuked them, so in the case of tit for tat warfare that you prescribe the last resort wasn't needed.
But they were still capable of fending off a ground invasion and willing to do so would have cost millions of lives in the end.
whomod said: I generally don't like it when people decide to play by the rules against people who don't play by the rules. It tends to put you immediately at a disadvantage and IMO is a sign of true weakness. This is true both in politics and on the internet."
