United Nations, the government of Earth. ARM agents are UN police. The UN became Earth’s sovereign government in the mid 21st Century, sometime after 2042.
Reference:World of Ptavvs, "The Ethics of Madness"
In 2326, a substate of the UN "Moscow Motors, that industrial giant subsidized by the substate USSR..." ("The Ethics of Madness", Neutron Star p. 183) .