Pretend to be a soldier writing a letter home explaining your reasons for
reenlisting after the battle of Bull Run.

The letter is below:

Dear mom:

I know that mentioned you that I would come back to home after to complete my mandatory time in the army, but we lost in front of the Confederate Army, and I feel that this war could change the country and the future of the people here, my spirit like American and my patriotism doesn't let me go home waiting the new recruits can do the feat that we didn't despite our experience, by this reason I decided reenlisting in the army. Please don't hate me, I'll do all in my hands to come back to the house and looking for a wife, as you ever wanted, to live a normal life in the farm and be near to you.

With love,

...

Explanation:

In the letter I used the patriotism and the American spirit, two strong feelings for the soldiers in war moments, they are usually the feelings that most accompany the soldiers and give them the courage to face terrible eventualities such as war, in addition to allowing them to endure trauma due to all the fateful scenes that are lived there.