 As Soviet archives opened in the 1980s, however, research found that the speech had little if any impact on Communist deliberations.With the Communist takeover of mainland China in 1949, that country switched from a close friend of the U.S. to a bitter enemy—the two powers were at war in Korea by 1950.Critics blamed Acheson for what they called the "loss of China" and launched several years of organized opposition to Acheson's tenure; Acheson ridiculed his opponents and called this period in his outspoken memoirs "The Attack of the Primitives".