The Liberty Defense Perimeter (LDP) was a 4,500 mile boundary line that served as the main purpose of the United States Department of War's plan for defending the United States against the Chimera. In the event of an alien invasion, the area within the LDP served as a sanctuary for humanity while the perimeter itself was fortified with armed defense towers. Final fortification of the line was completed in July 1952.
The Liberty Defense Perimeter was first conceptualized in September 17, 1950 by the US Mainland Defense Strategic Taskforce 3B in which they had analyzed enemy battle tactics and discussed hypothetical invasion scenarios regarding the imminent invasion by the Chimera on mainland America. Out of three scenarios, it was agreed that an attack from the coasts or from Alaska would overwhelm any resistance, but an attack from the northeast would allow for the creation of a heavily armed "Liberty Zone" in the southern United States and lead to a stalemate.
Two years prior to 1951, military and contracted civilian forces, working in conjunction with the Special Research Projects Administration began a lengthy surveying project for the LDP. President Noah Grace approved the construction of the LDP on September 3, 1951 after the New England region were hit by Spire attacks. The first leg of the fortress began along the northern quadrant of the U.S., set back approximately 300 miles from the Canadian border. This gave the nation a buffer zone of acceptable loss and provides the time to properly construct the LDP. The LDP was completed almost a year later on August 14, 1952. Eventually, the U.S. government is relocated to Denver.
On May 15, 1953, the United States was invaded by the Chimeran Fleet. After SRPA forces failed to deactivate the Holar Tower in Iceland, the Chimeran fleet launched a massive assault on the LDP at the southern perimeter on May 28, 1953. The Perimeter was then breached and roughly 63 million people were killed, including then President Harvey McCullen and his entire Cabinet after the Chimeran Fleet blanketed the area with Spire missiles. The U.S. military, however, managed to hold the last remaining protection camp in Baton Rouge, Louisiana. During the fighting the Chimera had sustained massive casualties to both ground forces and the air fleet, reducing the Chimeran Fleet to eighteen airships at the time of Operation Black Eden.
Under the U.S. Department of War's plans for evacuation, government, military, and civilian populations outside the LDP are evacuated in stages. Due to studies on the Chimera's swift conquest of Europe, officials grimly estimated that massive civilian causalities to be unavoidable during the evacuation. Furthermore, a premature evacuation was deemed to be detrimental as it would only cripple the American economy and devastate needed production as well as inciting mass panic. After key personnel are evacuated, the government will issue evacuation quotas for civil authorities that are still functioning during and after any invasion. Refugees who have no authentications, however, are discouraged, either by authority or force, from establishing camps or settlements at the border of the LDP.
Under the then presidency of Harvey McCullen, further evacuations were declared for American citizens living in the outside states to be move within the LDP in which an additional fifty protection camps were constructed inside the LDP in July 24, 1952, and more civilians were continuously evacuated through 1953.
- List A: Essential government personnel, House and Senate members, their families, and people on the Presidential list are the first to be evacuate.
- List B: Priority personnel and their immediate families (spouses, children, and parents living in the same home).
- List C: Primarily soldiers that are to be reassigned to defense towers and protection camps.
- List D: Second wave personnel who are assigned to combat the invasion and will be admitted to the LDP as part of an orderly retreat or with orders assigning them within the LDP.
The LDP is defended by a network of Liberty Defense Towers, which are averaging about 1400 feet tall and placed every 50 feet apart, each equipped with high-powered weaponry and state-of-the-art invasion detection technology. This comes to 38,780 towers along the whole of the Perimeter. The towers consisted of four crank 44mm gun emplacements surrounding a single large 90mm gun emplacement, and are armed with concussion shells that can fire at targets up to 50 miles away.
In contrary to popular demand, the LDP does not encompass the entire American coastal regions, as they are too disparate to be effectively sealed off from the threat of "outside aggressors." The cities which make up the corners of the LDP are: Twin Falls, Idaho; Springfield, Illinois; Columbus, Ohio; Knoxville, Tennessee; Mobile, Alabama; Montgomery, Alabama; New Orleans, Louisiana; Houston and Midland, both in Texas; Tucson, Phoenix; and Flagstaff, Arizona.
Further strategies were also proposed to hold out the United States in the invasion, which include the use of banned chemical weapons and the lowering of the draft age to 14. The Department of War also proposed a far from desirous solution known as the Masada Proposal: the complete eradication of military personnel, civilian contractors, and other civilians who are unable to be evacuate to the LDP in order to prevent them from being converted into Chimera and threatening the LDP. The only viable solution in the proposal includes poisoning water and food supplies of military bases and their surrounding areas.
Defense Tower Gallery
- Insomniac Games developed the LDP by using polygonal tools on Google Maps which they then shared through a chosen group of employees and made the Project Abraham Alternative-Reality Game mention it.
- In Resistance: Burning Skies, there are some photographs of the Liberty Defence Perimeter found in Richard Gorrell's office in Ellis Island, including the America First - America Only article, "OUR COASTLINES WILL BE DESTROYED".
- Also in Resistance: Burning Skies there is a cutscene where the director of the Liberty Defense Project, Mark Kirby, explains what the project is about.