Earth Strike Force was created when the UED did a counter attack against the zerg. The mission was only to destroy a small zerg outpost but ESF succeded so well so they got bigger missions in Terran space. On a special mission 25 years later, close to a planet whit top secret experiments, the contact to earth was broken. Towers started to fire uppon the ESF squad. The UED fleet opened fire upon ESF on the way back. They where accused for treson. Now days ESF is not allied whit the UED but still they will protect the Earth from zerg attacks. ESF found a little new colony of the protoss on a planet 21 light years away from earth. They created an allieans whit the portoss onthe planet, but are still called Earth Strike Force and are lojal to Earth but not to UED.