A region on the northwestern periphery of China which is inhabited by ethnic/linguistic/religious minorities, Xinjiang has been said (by Raffi Khatchadourian) to have "never seemed fully within the [Communist] Party’s grasp". Part of Xinjiang was once seized by Czarist Russia and it also had a short period of independence. Traditionally the People's Republic of China has favored an assimilationist policy towards minorities with the help of the mass immigration of Han Chinese into minority lands. After the collapse of its rival and neighbor the Soviet Union—also a huge multi-national communist state with one dominant ethnicity—the Chinese Communist Party was "convinced that ethnic nationalism had helped tear the former superpower to pieces". In addition, terrorist attacks were committed by Uyghurs in 2009, 2013, and 2014.