Later, his emigration to the United States was said to be motivated in part because he felt the government of Taiwan was suppressing him. He became a United States citizen in 1973–74, around the same time he left the "Taiwan Daily News". After leaving the newspaper, Liu published articles, essays and books that were critical of the Chiang family and associated people, including Chiang Kai-shek, Soong Mei-ling, Chiang Ching-kuo, K. C. Wu and Wang Sheng, with books on Long Yun and K. C. Wu planned at the time he was assassinated.