Árbenz was initially confident that his army would quickly dispatch the rebel force. The victory of the small Zacapa garrison strengthened his belief. However, the CIA's psychological warfare made the army unwilling to fight Castillo Armas. Gleijeses stated that if it were not for US support for the rebellion, the officer corps of the Guatemalan army would have remained loyal to Árbenz because although not uniformly his supporters, they were more wary of Castillo Armas; they had strong nationalist views, and were opposed to foreign interference. As it was, they believed that the US would intervene militarily, leading to a battle they could not win. On June 17, the army leaders at Zacapa had begun to negotiate with Castillo Armas. They signed a pact, known as the "Pacto de Las Tunas", three days later, which placed the army at Zacapa under Castillo Armas in return for a general amnesty. The army returned to its barracks a few days later, "despondent, with a terrible sense of defeat", according to Gleijeses.