Set in the 21st century, the board game begins with the premise that during the Cold War, nuclear terrorists destroyed much of the Middle East's supply of oil. In response, the United States launched into orbit a satellite based solar-power system to solve the energy crisis. At the same time, they had perfected the so-called "Star Wars" technology and incorporated a satellite-based laser system into the solar satellites. This system was capable of destroying intercontinental ballistic missiles (nuclear ICBM's) before impact. Thus, the USA was completely safe from nuclear threat, ending the era of Mutual Assured Destruction.
This creates a great deal of political turmoil - the USSR is especially upset at the nuclear balance of power being shifted - and while the rest of the world realigns in various ways (through alliances and treaties as well as conventional military conflict) the USA, complacent in its technical superiority, becomes isolationist in nature.
The game opens with the world divided into three major world powers outside of the US:
These three powers have launched a surprise assault on the now-conventionally-weak United States: Asian invaders on the Pacific coast, Central American invaders along the Southwestern border with Mexico, and the Euro-Soviet invaders along the eastern seaboard. The United States Navy is brushed aside. The land and air forces, still capable of resistance, are nevertheless insufficient to halt the invasions.
The unique nature of this game is the notion of three of four players cooperating together for the elimination of one player (the US). The game has an interesting dynamic of the US player being outnumbered 3-1 in military strength but steadily being reinforced by laser relay towers which each have a 60% chance to destroy an enemy unit anywhere on the board each turn. The rules of combat also favor the defender. Also, the invaders must place their reinforcements, which arrive on an even basis over the first few turns and then run out entirely, in their own invasion zones, which are sometimes far from the front, while the USA never runs out and can often be reinforced right at the front. The American player receives reinforcements by drawing two cards per turn, which sometimes specify for partisans or military forces to appear behind enemy lines. Others allow the USA to reconstruct shattered units from the dead pile in home cities, while all invading units are permanently out of play when lost in combat. The result is a rather exciting game that - if played well by all players - will result in a very close contest.
There are 30 cities represented on the board and the invaders must capture, and hold until the end of an entire turn, 18 or more of them to win the game. This allows the USA one round to counterattack and recapture after all the invaders have played a round and temporarily achieved their goal of 18.
Commercially, this was considered to be the third most successful board game in Milton Bradley's Gamemaster Series. In 1987, Fortress America won the Charles S. Roberts for Best 20th Century Game of 1986.