Although Khanh had seized power in January 1964 in alliance with Khiem, the pair had soon fallen out over policy disputes along religious lines, and the Catholic Khiem began to plot against Khanh. Khiem was believed to have helped plan a failed coup in September 1964, and Khanh exiled him as a result. While in Washington, Khiem continued to plot alongside his aide Thao, who was actually a communist agent bent on trying to foment infighting at every opportunity. Aware of Thao's plans, Khanh summoned him back to Vietnam in an apparent attempt to capture him, and Thao responded by going into hiding and preparing for his attack. In the meantime, Khanh's hold on power was slipping as his military support dwindled, and he became increasingly reliant on the support of civilian Buddhist activists