Domestic Terrorism Prevention Act of 2019 This bill authorizes domestic terrorism offices in the Department of Homeland Security (DHS), the Department of Justice (DOJ), and the Federal Bureau of Investigation (FBI) and requires specified steps to prevent and report on domestic terrorism. The bill also authorizes a Domestic Terrorism Executive Committee, which shall coordinate with key public safety officials to promote information sharing and ensure an effective joint effort to combat domestic terrorism. The joint terrorism task forces of the FBI and state, local, and regional fusion centers shall each, in coordination with the committee and such offices (1) share intelligence to address domestic terrorism activities; (2) conduct an annual, intelligence-based assessment of domestic terrorism activities in their jurisdictions; and (3) formulate and execute a plan to address and combat such activities. DOJ, the FBI, DHS, and the Department of Defense shall establish an interagency task force to combat white supremacist and neo-Nazi infiltration of the uniformed services.