Mr. President: The American Presidency, 2001-2020 2nd Edition Update Kit

You'll note that's most of the Booklets and PACs in the game! Some of this is to accommodate errata and clearer wording from the FAQ for the 2nd Edition, but it will also include numerous game enhancements to make the game more challenging (especially in years 3 and following) and to add features, importance, and more difficult choices to areas like:

Ally Relationships/Actions

Strategic Capabilities

Combat (Counterattacks, Carrier Support and Combat DRMs based on Strategic Capabilities, Heavy units less useful in Guerrilla War)

Iran at War (including a new Action Table)

Cascading Events (January Surprise)