You are actually for once at least partially right. It is difficult for people nowdays to
The truth however, is that the nuclear bomb was not nearly as much of a factor in the Japanese surrender as people tend to think. At the time, the US Airforce had complete unopposed control of the Japanese air. They were levelling the Japanese cities anyway. For example, the firebombing of Tokyo on 23 Feb killed more people than the bomb at Hiroshima did (80,000 - 100,000). The only reason that so many people died at Hiroshima was that it had been a "safe city" that had not recieved attention from the USAF before and was therefore full of refugees from all the other cities that had already been flattened. The three raids on Tokyo in Feb - Mar '45 utterly destroyed 80 square kilometers of city. total US losses were 22 aircraft. By August '45, they were losing 0 aircraft in these raids. Bottom line is that the US simply didn't need the A-Bomb to wreak far more damage than was done at Hiroshima and had been doing so since January '45.
The whole moral argument arround the use of the bomb is irrelevant. It is utterly irrelevant to the dead weather they were killed by 1 B29 with 1 bomb, or 334 B29s, dropping thousands of bombs. Now you can make an argument about wether the allies should have continued strategic bombing as long as they did (particularly in Germany), but the type of bombs they used is unimportant.
There was a lot of stuff going on around the time of the surrender and a lot of things contributed to the actually surrender. Japan had without a doubt lost the war at least a year earlier. Unlike in Germany, their leadership wasn't waiting for a miracle to turn the tide. But a strong faction within the military controled government (lets call them the Bittereinders) just did not want to surrender and in fact wanted a US invasion of the home islands during which the Japanese people could go out fighting. So yep, they perfered the total destruction of the Japanese people, to surrender. (Are they militant enough for you alan85). Hirohito was a very week emmperor and he bas utterly dominated by these guys. This faction was never persuaded to surrender. Hirohito however finally had the balls to make the hard decisions in order to save his people.
So yes, the A-Bomb was a factor, but so were many other considerations like Japan had no chance of staving off defeat, the enourmous and mounting death toll, the fact that while the Americans were bombing refugees in Hiroshima, the Russians had declared war on Japan and utterly overrun the entire Japanese army in Manchuria in a little less than two weeks, and then occupied the Kurile Islands. Also the American's offer of immunity to Hirohito and promise not to overly aggressively persue war crimes prosecutions was a consideraton.