The US has huge interests in Hong Kong. In 1992, a few years before China resumed its sovereignty over Hong Kong in 1997, the US adopted the U.S.-Hong Kong Policy Act of 1992. The keynote of the Act is to enhance the cooperation with and maintain the treatment to Hong Kong. This tune has changed in the Hong Kong Human Rights and Democracy Act of 2019, which is obviously the response of the US to widespread protests in Hong Kong arising from the Extradition Bill proposed by the Government of Hong Kong SAR. The new law includes several negative elements. It marks a change in the US policy towards Hong Kong and furthermore represents a change in the US policy towards China. The new law should not merely be understood as the US’s support for democracy and human rights in Hong Kong. Instead, it should be considered as a major leverage which the US may maneuver to engage a rising China.