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 Liberty Defense Towers. Final fortification of the line was completed in July, 1952.
- Main article: SCNR458849
The idea for the creation of the Liberty Defense Perimeter was first mentioned in an analysis of enemy battle tactics. Discussing hypothetical invasion scenarios, the document (SCNR458849) notes that while an attack from the coasts or from Alaska would overwhelm any resistance, 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. It appears that the government used the Liberty Zone concept as inspiration for the LDP project.
Two years prior to 1951, concentrated military and civilian forces, working in conjunction with the Special Research Projects Administration began a lengthy surveying project for the LDP. On August 14th, 1951, the state of New York became the first place on American soil to be attacked by Chimeran Spires, and by August 20th, much of the New England territory had fallen under the Chimera. In response to the unprecedented attacks, President Noah Grace approved the construction of the LDP on September 3rd, which was completed almost a year later on August 14th, 1952.
Once the inevitable invasion begins, the government will be moved inside the LDP specifically Denver, Colorado as the temporary capital, followed shortly thereafter by essential personnel, House and Senate members, and priority personnel, as well as any immediate family members they may have. They will be followed by military forces assigned to guard the zone. Once they have arrived, civil authority will allow for some groups of civilians to enter the area.
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 24th, 1952, and more civilians were continuously evacuated through 1953.
The United States War Department established the Liberty Defense Tower program, which consists of a series of 50 foot tall towers placed every 1,400 feet along the LDP. This comes to 38,780 towers along the whole of the Perimeter. The towers consisted of four crank 44mm emplacements surrounding a single large 90mm emplacement, and are armed with concussion shells that can fire at targets up to 50 miles away. In contrary to popular demand, the LDP would not encompass the coastal regions of America, as they are too disparate to be effectively sealed off from the threat of outside aggressors. 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 gives the nation a buffer zone of acceptable loss and provides the time to properly construct the LDP.
President Grace approved construction of the buildings, and they were scheduled to be completed in September 1951. 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.
An additional plan known as the Masada Proposal suggested the idea of poisoning water and food in the area outside of the LDP. This will prevent the invaders from infecting humans and turning them into Chimera. Use of banned chemical weapons and the lowering of the draft age to 14 have also been proposed.
Defense Tower Gallery
Breach and destruction
After SRPA forces failed to deactivate the Holar Tower in Iceland, Chimeran forces launched a massive assault on the LDP at the southern perimeter on May 28th, 1953. The Perimeter was then breached and roughly 63-80 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 as since there were only eighteen Chimeran airships at the time of Operation Black Eden.
- 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 layout and a photograph of the Liberty Defence Perimeter in newspapers, found in Richard Gorrell's office in Ellis Island with words "OUR COASTLINES WILL BE DESTROYED" before Ellie Martinez and Tom Riley retrieve the film and escape from SRPA Station Kali.