Truman could have relied on the B-29 firebombing raids on Japan's cities that could have combined with the naval blockade to wear down the Japanese resistance and force their surrender. Scholars that were critical of this approach pointed out that the bombing may have taken some time to force a surrender putting American pilots, troops and sailors at risk. Way more Japanese would have died using this option, than were killed in the two atomic raids.
2. Demonstrate the atomic bomb. By demonstrating the atomic bomb, Truman could have shown the Japanese leaders, including Hirohito, that their nation faced total destruction if they did not surrender immediately. Other scholars pointed out