Sons of the Patriots

SOP (standing for Sons Of the Patriots, sometimes referred to as simply The System) is an advanced system that allows the government to track and keep check on every soldier deployed in combat action. It was developed by ArmsTech Security.

The system also allows several members of a military unit to share each other's senses and work more efficiently as a team. This provides a massive tactical advantage to whomever uses it. Soldiers do not feel fear or remorse and fight without regard for their own safety. SOP can also induce an artificial "combat high", elevating the senses and accuracy of every soldier, as well as keeping him or her well nourished and suppressing any medical ailments that might impact performance. Another major function of the System is being able to keep check of whomever is using certain weapons and locking if a problem arises (such as if their gun is stolen and being used by someone else, or if they start shooting their comrades, etc.) Apart from soldiers, guns, ammo, tanks, vehicles, and even ballistic missiles are under the watch of SOP. The system also is described to keep soldiers from shooting their superior officers (for a PMC's case, keeping them from shooting their contractors or turning against them) and stops them from committing atrocious acts and violating human rights, as Colonel Campbell described. The system also prevents somewhat minor injuries from getting in the way during combat and can quickly heal a wound, as evident by Jonathan being shot by a FROG, only to nudge the wound off as if nothing happened. However, the system does not control one's usual personality, such as Meryl being in a rage after hearing of Campbell from Snake at the Middle East and Raven Sword soldiers being foul-mouthed towards a disguised Snake in eastern Europe.

As of 2014, all state armies and PMC's are known to have the SOP implanted in them and even law enforcement agencies and paramilitaries were adopting them. Of course, militias and rebel armies did not have access to the system, which explains why they lost many battles to state armies. Meryl's Rat Patrol 01 team is one example.

Liquid Ocelot, being the head of the PMC Mother Company Outer Heaven, had built an army with enough firepower to rival the US Military and was intending to use this massive army to challenge The Patriots. However, thanks to the limitations of The System he was unable to attack them as he knew they would simply lock his entire army down. What Liquid originally intended to do was take the system offline, but to do this he required the cells of Big Boss which acted as a key to the system. He conducted two tests on his own PMC troops, one in the Middle East and one in South America using his own cells and then the cells of his brother Solid Snake. While both these tests partially succeeded in disabling the system from within his troops, they were suddenly bombarded with guilt over the horrible things they had done under the systems controls and most of them were driven to the brink of insanity. Otacon also mentioned that some of the PMC soldiers even died of heart attack when the system controls over them were gone.

Even though Liquid had a foot in the door by piecing together the broken GW AI, it was not enough to access SOP directly. He later stole Big Boss' corpse from Big Mama and used it to fully gain control of SOP (it was later revealed that the corpse was actually the corpse of Solidus Snake, but his genes were identical to that of Big Boss, so there was no difference). With SOP under Liquid's control, private armies around the world were crippled, with national armies under trained and under equipped to deal with the threat. Roy Campbell referred to it as "the first ever total cease fire in history".

The Sons of the Patriots system was destroyed by the FOXALIVE virus created by Naomi Hunter and Sunny, along with the rest of the Patriots' AI matrix. However, with the system destroyed, this would also cripple PMCs as well as state armies worldwide, leaving behind a uncertain fate.

Metal Gear Online
In Metal Gear Online, the SOP system allows players to see where their teammates are at any given time and allows them to send and receive help messages from allies, however the system needs to be activated by standing next to a comrade and pressing/holding the Triangle button. The player can also capture an enemy and hack into their SOP system to allow them to see where enemies are. The system can also prevent them from firing for a few seconds if they accidentally shoot one of their own team-mates.