Beijing has governed Hong Kong under the “one country, two systems” principle since the former British colony returned to Chinese rule in 1997. Before the transfer of sovereignty, the two sides signed a joint treaty, the Sino-British Joint Declaration registered at the United Nations, to guarantee a high degree of autonomy for Hong Kong, including a separate judiciary system, for 50 years after the handover.
The proposed national security law will bypass the regular lawmaking process in the Hong Kong legislature, raising concerns over whether it is a breach of Hong Kong’s autonomy. There is fear the national security laws could lead to Chinese intelligence agencies setting up bases in Hong Kong and enforcing law directly.
Article source: https://www.cnbc.com/2020/05/28/china-national-security-proposal-for-hong-kong-what-we-know-so-far.html