Should the US have dropped the atomic bomb on Japan?

Personally, I feel that the dropping of the atomic bomb was unjustified. In fact, I think that the creation of the atomic bomb was a mistake to begin with. To begin, the geneva convention already states that any people not directly taking part in the war, including civilians, are not to be harmed.

Also, it is morally incorrect to claim the lives in a whole city just because the country is at war with your own. When the Americans dropped the atomic bomb on Hiroshima and Nagasaki, they had no intention of sparing any civilians nor providing an easy solution to Japan. It wiped out the two entire cities and its radioactive effects still linger to this day, probably taking thousands of years to dissipate.

During the time of world war 2, despite Japan's military victories, its economy was already collasping. Its precisely because of this that they could not fund their military, thus using Kamikaze as their last resort. Considering this, if the war was to continue for a few more months, Japan would have already had no option but to withdraw, thus they were fighting a losing battle. In such a case, it would be effortless for America to purely sustain a simple war of Attrition, giving no excuses for the dropping of the atomic bomb.

Considering the destructive effects of such a weapon, one must consider if the innocent lives claimed can account for winning the war.