Combat Violent Crime Act of 2019 This bill alters the approach used by courts to determine if a criminal offense constitutes a crime of violence for the purposes of imposing an enhanced sentence on a defendant who uses or possesses a firearm in a crime of violence. Currently, the term crime of violence means a felony that (1) has as an element the use, attempted use, or threatened use of physical force; or (2) by its nature, involves a substantial risk of physical force. To determine if an offense constitutes a crime of violence under the second prong, courts apply a categorical approach to assess whether the nature of the defendant's offense, based on its statutory elements, involves a substantial risk of physical force. In 2019, the Supreme Court held in United States v. Davis that the categorical approach (i.e., assessing the nature of the defendant's offense based on its statutory elements) is unconstitutionally vague. This bill revises the second prong of the crime of violence definition to mean a felony that, based on the facts underlying the offense, involved a substantial risk of physical force. Under the revised definition, courts would apply a conduct-based approach to determine if an offense constitutes a crime of violence. The conduct-based approach assesses whether the defendant's conduct underlying an offense, based on the facts of the case, involved a substantial risk of physical force.