From the Arab Legion's inception, its primary mission was the establishment of the central government's authority through the maintenance of public order and the preservation of internal security. It was originally composed of Arabs from the defeated Ottoman armies and others from outside the amirate. Under the early agreements between Transjordan and Britain, defense of the borders against external attack remained a British responsibility. To this end, a British Royal Air Force (RAF) squadron and British army armored car unit were stationed in the country. In 1924 they joined with the Arab Legion to beat back a Wahhabi invasion from the area to the south that within a few years became Saudi Arabia. The ability of the legion to protect the amirate from outside raids helped to cement the legitimacy of Hashimite rule.

By 1926 the Arab Legion had established an image as the protective arm of the central government, functioning as an agency for tax collection as well as for security. The bedouins remained wary and hostile, however, convinced that the legion strengthened the hand of the regime, whose purposes they mistrusted. Initially the bedouins refused to join the legion, thus forcing reliance on villagers and townspeople to replenish its personnel.

In early 1926 the British high commissioner for Palestine created the Transjordan Frontier Force (TJFF) to defend Transjordan's northern and southern borders. The legion immediately incurred a loss of more than half of its forces when they were transferred as cadre for the new border security force. In addition to the drop in personnel, the legion also was stripped of its machine guns, artillery, and communications troops. The much reduced force reverted to a role of policing the towns and villages. The TJFF (roughly 1,000 officers and men) never was part of the legion and was responsible to the British high commissioner in Jerusalem rather than to Amir Abdullah of Transjordan. All officers above the rank of major were British. Officers of lesser rank were Arabs, Circassians, and Jews, but the promotion system precluded the advancement of any Middle Easterners to a position of command over British troops.

With its effectiveness reduced by creation of the TJFF, the Arab Legion was unable to cope with raids by tribal groups in the vast desert regions of Transjordan during the late 1920s and early 1930s. To counter these disturbances, a British captain was transferred to the legion as second in command to Peake. This officer--later to become known as Lieutenant General Sir John Bagot Glubb, or Glubb Pasha, the strongman of Jordan--had previously faced similar pacification problems while serving in the Iraqi government. Glubb understood the bedouins and had acquired a knowledge of strategy and tactics required for long-range desert operations. Under his command a camel-mounted Desert Mobile Force was organized in 1930, reflecting its leader's concepts of a military unit functioning in a desert environment. The Desert Mobile Force, which eventually merged with the Arab Legion, attracted principally bedouins to its ranks, establishing191 ng the identification of the bedouins with the monarchy that has persisted through Hussein's reign.

Data as of December 1989