Reason 1: The Republican and Democrat party platforms are lengthy and specific, which make it easy to create legislation cards to fulfill their platform goals. Reason 2: Time and Money. We want to create "third party" expansion packs after our Kickstarter.
FAQ: Where is the Defense platform?
While decisions about war and defense should go through Congress, they typically don't, as the President is Commander-in-Chief. As important as it is, it doesn't fit the game as created. Source: Council on Foreign Relations