The long years of strife between the liberal and conservative political factions and the existence of private armies led the United States to sponsor the National Guard as an apolitical institution to assume all military and police functions in Nicaragua.

[5] Sandino opposed the United States-backed military force, which was composed mostly of his political enemies, and continued to resist the marines and the fledgling National Guard from a stronghold in the mountainous areas of northern Nicaragua.

[5] Although Nicaragua was not actively involved in World War II, it qualified for United States Lend-Lease military aid in exchange for U.S. base facilities at Corinto.

[5] United States military aid to the National Guard continued under the Rio de Janeiro Treaty of Mutual Defense (1947), but stopped in 1976 after relations with the administration of Anastasio Somoza Debayle (1967–72, 1974–79) worsened.

[5] Some United States equipment of World War II vintage was also purchased from other countries—Staghound armored cars and M4 Sherman medium tanks from Israel and F-51 Mustang fighter aircraft from Sweden.

[5] The guard's domestic power, however, gradually broadened to embrace not only its original internal security and police functions but also control over customs, telecommunications, port facilities, radio broadcasting, the merchant marine, and civil aviation.

[6] These two groups, contrary to the original Puntarenas Pact were controlled by the Sandinistas and trained by personnel from Cuba, Eastern Europe, and the Soviet Union.

[6] Meanwhile, the EPS developed, with support from Cuba and the Soviet Union, into the largest and best equipped military force in Central America.

[6] Simultaneously, with the introduction of Patriotic Military Service (1983), a conscription system, EPS forces reached approximately 80,000 active-duty members by 1990.

In this context, it was discovered that the government's “usual response…was to investigate and discipline those responsible.”[8] Under an agreement between President-elect Chamorro of the National Opposition Union (Unión Nacional Oppositora – UNO) and the defeated FSLN party, General Humberto Ortega, former defense minister and commander in chief of the EPS under the Sandinistas, remained at the head of the armed forces.

[9] Ortega challenged her authority to relieve him and reiterated his intention to remain at the head of the EPS until the army reform program was completed in 1997.

[9] The size of the army declined from a peak strength of 97,000 troops to an estimated 15,200 in 1993, accomplished by voluntary discharges and forced retirements.

[9] Under the Sandinistas, the army general staff embodied numerous branches and directorates artillery, combat readiness, communications, Frontier Guards, military construction, intelligence, counterintelligence, training, operations, organization and mobilization, personnel, and logistics.

[9] A small EPS contingent works alongside demobilized Contras in a Special Disarmament Brigade to reduce the arsenal of weapons in civilian hands.

[10] The Nicaraguan military, Fuerzas Armadas de Nicaragua, exists in a top-down hierarchy and is partitioned into multiple ranks.

[20] Such a small military budget has resulted in severe deficiencies in terms of manpower (i.e. cannot supply and employ) and modern weaponry.