The Independent Colonial Strategic Alliance (ICSA) is an unaligned version of the Interplanetary Strategic Alliance, created to give aid to completely independent worlds.
The ICSA seems to make few demands and offers large amounts of help to independent colonies. In 2223, the ICSA offered membership and support to the Helghast decades after the First Extrasolar War. But all offers were refused by the understandably paranoid Helghast, who are wary of outside influences. In 2350, the ICSA helped end Helghan's economic depression after the Helghan Empire secured a contract with the ICSA for energy and materials.
During the Second Extrasolar War, the ICSA pleaded for a diplomatic solution to the conflict, weeks before the ISA invasion of Helghan. These pleas seem to have been ignored, possibly a result of the ICSA alienating itself in the first place.
- The ICSA is mentioned twice in some intel in Killzone: Mercenary. Both mention "the breakaway colonies of the ICSA", which suggests the ICSA is not just some obscure organization and is actually fairly successful in its efforts to support colony worlds that attempt independence. The Phantom Talon Corp is said to have been involved in disputes on ICSA colony worlds.