Creates a new federal crime that makes it illegal to knowingly assault a first responder who is performing official duties if the assault causes serious bodily injury. The law sets prison penalties (up to 10 years for serious bodily injury; longer terms, including life, if the assault results in death, kidnapping, or an attempted killing) and specifies when the federal government can prosecute the offense, such as when interstate travel or commerce is involved or the victim is a Federal first responder. Before the United States can bring most prosecutions under this law, the Attorney General must provide a written certification authorizing the case.