With great power comes great responsibility, and great indeed are the possibilities afforded you by the new Stars & Stripes DLC for Hearts of Iron III.
Focusing on the USA this DLC factors in such things as the Great Depression and recession issues, while uniquely presenting scenarios about operations Overlord and Downfall, introducing new Lend-Lease mechanisms, letting you lead famous US divisions (Rangers, 101st Airborne, etc), allowing the selective boosting of AI to potentially bring about World War III, plus a number of other refinements, graphical improvements to user interface and unit models.
What if you don't embargo Japan and let them conquer Asia as they like, then preventing Pearl Harbor to happen? What if you join the war in '39? What if you focus on Japan and don't help the Allies in Europe? What if you support totalitarian countries and go Axis, then send Lend Lease to Germany (the world is doomed!)?
If this appeals to you, then drop by GamersGate or Steam and take up the star-spangled banner.