This campaign period was from 15 March 1962 to 7 March 1965. During this period, direct U.S. involvement in the Vietnam conflict increased steadily as U.S. trained Vietnamese pilots moved Vietnamese helicopter units into and out of combat. Ultimately the United States hoped that a strong Vietnamese government would result in improved internal security and national defense. The number of U.S. advisors in the field rose from 746 in January 1962 to over 3,400 by June; the entire U.S. commitment by the end of the year was 11,000, which included 29 U.S. Army Special Forces detachments. These advisory and support elements operated under the Commander, U.S. Military Assistance Command, Vietnam, a position established 8 February 1962. The object of American military assistance was to counter the threat to the government of the Republic of Vietnam posed by the insurgency of an estimated 30,000 regular communist Viet Cong and civilian sympathizers among the population. Despite what appeared to be considerable successes in consolidating the population in a series of defended strategic hamlets, and in establishing local defense forces, the U.S. equipped Army of the Republic of Vietnam repeatedly demonstrated an unwillingness to close with the enemy. A corrupt government and bitterly contending Vietnamese political factions further hampered a coherent prosecution of the war with American advisors, who nevertheless continued their efforts well into the period of large scale commitments of U.S. Army forces to the conflict.