If I remember correctly, he commit suicide because he couldn't handle the punishments coming his way. People found out about the bad things he did, such as the Holocaust, and they prepared to make him pay for what he did.
He knew this, and he didn't want to face the consequences for his actions, knowing that it'd be a LARGE punishment, so he ended his life.
<span>Assuming that this is referring to the same list of options that was posted before with this question, you would want to talk about the idea of "Manifest Destiny" since this was the main driving force of expansion. </span>
