The United States and other nations increasingly rely on private contractors, many of them armed, to guard military bases, protect diplomatic personnel, conduct surveillance of potential military targets and carry out other such duties. Over the past decade, security companies have greatly increased in number and size, becoming a major industry that attracts private-sector clients as well. Multinational corporations hire the same armed contractors that governments use to guard remote mining operations, and shipping companies hire them to fight pirates. Governments and other clients say private guards save money and provide strategic flexibility. Critics argue, however, that using soldiers-for-hire gives governments too much leeway to take armed actions without citizens' or lawmakers' consent. Furthermore, they contend, no system of law -- national or international -- holds armed contractors or those who hire them fully accountable for human-rights violations.

Marcia Clemmitt is a veteran social-policy reporter who joined CQ Researcher after serving as editor in chief of Medicine and Health, a Washington-based industry newsletter, and staff writer for The Scientist. She has also been a high school math and physics teacher. She holds a bachelor's degree in arts and sciences from St. Johns College, Annapolis, and a masters degree in English from Georgetown University.