LeMay and Harris had no illusions about their actions not being war crimes and their culpability as war criminals if the allied commanders were to face post-war trials. Here are a couple LeMay quotes:
"There are no innocent civilians."
"I suppose if I had lost the war, I would have been tried as a war criminal. Fortunately we were on the winning side."
Sounds like criminal intent and admission of guilt to me. Regarding the effectiveness of Dresden bombing, it certainly did not achieve the goal of breaking German will to fight. If anything, it was used as a very effective propaganda tool by Goebbels on why Germans should not surrender. "Shock and Awe" policies just don't work very well in the modern age like it supposedly worked for the Mongol Hordes on sacking cities. The Nazi extermination policies on the eastern front, the London Blitz, the Soviet rape campaigns in East Prussia, the Japanese massacres in China, and the allied massive bombings on civilian targets served mostly to stiffen resistance instead of cowering the enemy population. The reason IMHO is due to modern communication technologies in the 20th century could cause more people outside the immediate massacre zone to be outraged than the number of people in the massacre zone to be cowered. Sure the people of Dresden and Konigsberg may have been cowered, but the remaining 99+% of the German population was outraged.
The situation in bombing Japan was a little more nuanced: the emperor already made up mind to surrender in March, almost 5 months before the nuclear bombs. That's why he appointed the Suzuki cabinet. The critical issue was how to surrender without army coup by mid-level officers; historically it was a close race anyway. The firebombing of Tokyo on the night of March 9-10 demonstrated to the Emperor that he could be personally in danger of being destroyed. Whether it had to destroy 200,000 civilians in one night to prove that point was questionable.
By the time of Dresden and Tokyo bombings, the issue of whether the United Nations (Allies) or the Axis Powers would win the war was long a foregone conclusion. Japan no longer had a merchant fleet by early 1945; that's for a nation that imported nearly 100% of its oil requirement. We are not at all talking about the earlier bombing campaigns in 1943 and early 1944 that served the military purpose of destroying Luftwaffe and the aircrafts/major war-making factories in Germany and Japan. Dresden hardly had any munition factory by then; the 16 square miles burned out in Tokyo was a sector of civilian housing, with a bombing method explicitly worked out to optimize destruction of Japanese civilian residences.