Dear Mr. Truman,
First of all, I have a great deal of respect for you. It must have been hard to suddenly be plunged into presidency so quickly. I know that you were quickly informed of the Manhattan Project. It must have been hard to pick the option of dropping the atom bombs on Japan. War is an ugly thing, and you had to quickly take leadership of the U.S. and decide the actions that America would take.
I completely agree with your actions of choosing to use the atomic bombs. Without it, America would have needed to invade the Japanese homeland, and the Japanese are fierce fighters. The invasion would have cost thousands of American lives. Thankfully, you made this sacrifice unnecessary by bombing two cities and patiently waiting for word of the Japanese surrender. That must have not been easy.
Whether you know it or not, you have made a huge difference on history. You are the man that was suddenly put into the highest office in the land and quickly adjusted, making sound decisions in the middle of war. We all appreciate your work for America.